Ships with CentOS 6
OpenSSH 5.3p1 vulnerabilities
OpenSSH 5.3p1 ships with CentOS 6. The US National Vulnerability Database lists 60 vulnerabilities for this version, 3 of them critical. OpenSSH fixes flaws only in its newest release. Distributions backport those fixes while they are supported and stop at end of life.
- 60known vulnerabilities
- 3critical
- 13high
- 0exploited in the wild
Is OpenSSH 5.3p1 affected?
| Vulnerability | CVE | OpenSSH 5.3p1 |
|---|---|---|
| regreSSHion | CVE-2024-6387 | Not affected |
| Terrapin | CVE-2023-48795 | Affected |
For the upstream version, according to the US National Vulnerability Database. Your distribution may have backported a fix before its end of life.
What you can do
Keep OpenSSH 5.3p1, patched
We backport the security fixes to the OpenSSH package of your distribution, built and tested before delivery. A fix for a new vulnerability arrives within 48 hours of your order, or within 24 hours with priority delivery.
Upgrade
Move to a supported distribution and its newer OpenSSH, once your servers can make the jump. Our fixes keep you safe while you plan it.
Assess first
Our assessment shows which vulnerabilities are real on your servers, what else is past end of life, and the remediation plan.
All 60 known vulnerabilities in OpenSSH 5.3p1
US National Vulnerability Database, 28 October 2026, highest score first. Fixed in: the first upstream release with the fix, where NVD records it. Exploited: listed in the CISA catalogue of known exploited vulnerabilities. Distribution builds may already include fixes for some of them.
| CVE | Score | Severity | Published | Fixed in | Description |
|---|---|---|---|---|---|
| CVE-2010-4478 | 9.8 | Critical | 2010-12-06 | n/a | OpenSSH 5.6 and earlier, when J-PAKE is enabled, does not properly validate the public parameters in the J-PAKE protocol, which allows remote attackers to bypass the need for knowledge of the shared secret, and successfully authenticate, by sending crafted values in each round of the protocol, a related issue to CVE-2010-4252. |
| CVE-2016-1908 | 9.8 | Critical | 2017-04-11 | 7.2 | The client in OpenSSH before 7.2 mishandles failed cookie generation for untrusted X11 forwarding and relies on the local X11 server for access-control decisions, which allows remote X11 clients to trigger a fallback and obtain trusted X11 forwarding privileges by leveraging configuration issues on this X11 server, as demonstrated by lack of the SECURITY extension on this X11 server. |
| CVE-2023-38408 | 9.8 | Critical | 2023-07-20 | 9.3 | The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system. (Code in /usr/lib is not necessarily safe for loading into ssh-agent.) NOTE: this issue exists because of an incomplete fix for CVE-2016-10009. |
| CVE-2015-5600 | 8.1 | High | 2015-08-03 | n/a | The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list. |
| CVE-2015-8325 | 7.8 | High | 2016-05-01 | n/a | The do_setup_env function in session.c in sshd in OpenSSH through 7.2p2, when the UseLogin feature is enabled and PAM is configured to read .pam_environment files in user home directories, allows local users to gain privileges by triggering a crafted environment for the /bin/login program, as demonstrated by an LD_PRELOAD environment variable. |
| CVE-2016-10012 | 7.8 | High | 2017-01-05 | n/a | The shared memory manager (associated with pre-authentication compression) in sshd in OpenSSH before 7.4 does not ensure that a bounds check is enforced by all compilers, which might allows local users to gain privileges by leveraging access to a sandboxed privilege-separation process, related to the m_zback and m_zlib data structures. |
| CVE-2026-60002 | 7.7 | High | 2026-07-08 | 10.4 | ssh in OpenSSH before 10.4 can have a use-after-free when a server changes its host key during a key re-exchange. (This outcome occurs only on the client side.) |
| CVE-2010-5107 | 7.5 | High | 2013-03-07 | n/a | The default configuration of OpenSSH through 6.1 enforces a fixed time limit between establishing a TCP connection and completing a login, which makes it easier for remote attackers to cause a denial of service (connection-slot exhaustion) by periodically making many new TCP connections. |
| CVE-2016-10708 | 7.5 | High | 2018-01-21 | 7.4 | sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an out-of-sequence NEWKEYS message, as demonstrated by Honggfuzz, related to kex.c and packet.c. |
| CVE-2016-6515 | 7.5 | High | 2016-08-07 | n/a | The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string. |
| CVE-2026-35385 | 7.5 | High | 2026-04-02 | 10.3 | In OpenSSH before 10.3, a file downloaded by scp may be installed setuid or setgid, an outcome contrary to some users' expectations, if the download is performed as root with -O (legacy scp protocol) and without -p (preserve mode). |
| CVE-2020-15778 | 7.4 | High | 2020-07-24 | 8.3 | scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument. NOTE: the vendor reportedly has stated that they intentionally omit validation of "anomalous argument transfers" because that could "stand a great chance of breaking existing workflows." |
| CVE-2014-1692 | 7.3 | High | 2014-01-29 | n/a | The hash_buffer function in schnorr.c in OpenSSH through 6.4, when Makefile.inc is modified to enable the J-PAKE protocol, does not initialize certain data structures, which might allow remote attackers to cause a denial of service (memory corruption) or have unspecified other impact via vectors that trigger an error condition. |
| CVE-2016-10009 | 7.3 | High | 2017-01-05 | n/a | Untrusted search path vulnerability in ssh-agent.c in ssh-agent in OpenSSH before 7.4 allows remote attackers to execute arbitrary local PKCS#11 modules by leveraging control over a forwarded agent-socket. |
| CVE-2015-6564 | 7.0 | High | 2015-08-24 | n/a | Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request. |
| CVE-2016-10010 | 7.0 | High | 2017-01-05 | n/a | sshd in OpenSSH before 7.4, when privilege separation is not used, creates forwarded Unix-domain sockets as root, which might allow local users to gain privileges via unspecified vectors, related to serverloop.c. |
| CVE-2019-6109 | 6.8 | Medium | 2019-01-31 | n/a | An issue was discovered in OpenSSH 7.9. Due to missing character encoding in the progress display, a malicious server (or Man-in-The-Middle attacker) can employ crafted object names to manipulate the client output, e.g., by using ANSI control codes to hide additional files being transferred. This affects refresh_progress_meter() in progressmeter.c. |
| CVE-2019-6110 | 6.8 | Medium | 2019-01-31 | n/a | In OpenSSH 7.9, due to accepting and displaying arbitrary stderr output from the server, a malicious server (or Man-in-The-Middle attacker) can manipulate the client output, for example to use ANSI control codes to hide additional files being transferred. |
| CVE-2012-0814 | 6.5 | Medium | 2012-01-27 | n/a | The auth_parse_options function in auth-options.c in sshd in OpenSSH before 5.7 provides debug messages containing authorized_keys command options, which allows remote authenticated users to obtain potentially sensitive information by reading these messages, as demonstrated by the shared user account required by Gitolite. NOTE: this can cross privilege boundaries because a user account may intentionally have no shell or filesystem access, and therefore may have no supported way to read an authorized_keys file in its own home directory. |
| CVE-2014-2653 | 6.5 | Medium | 2014-03-27 | n/a | The verify_host_key function in sshconnect.c in the client in OpenSSH 6.6 and earlier allows remote servers to trigger the skipping of SSHFP DNS RR checking by presenting an unacceptable HostCertificate. |
| CVE-2016-0777 | 6.5 | Medium | 2016-01-14 | n/a | The resend_bytes function in roaming_common.c in the client in OpenSSH 5.x, 6.x, and 7.x before 7.1p2 allows remote servers to obtain sensitive information from process memory by requesting transmission of an entire buffer, as demonstrated by reading a private key. |
| CVE-2023-51385 | 6.5 | Medium | 2023-12-18 | 9.6 | In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host name has shell metacharacters, and this name is referenced by an expansion token in certain situations. For example, an untrusted Git repository can have a submodule with shell metacharacters in a user name or host name. |
| CVE-2026-106585 | 6.5 | Medium | 2026-10-06 | 10.6 | In sshd and ssh in OpenSSH before 10.6, there is no check for whether the maximum packet length is exceeded during decompression of highly compressed data. |
| CVE-2026-60001 | 6.5 | Medium | 2026-07-08 | 10.4 | sshd in OpenSSH before 10.4 does not always honor the minimum authentication delay. |
| CVE-2015-6563 | 6.4 | Medium | 2015-08-24 | n/a | The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c. |
| CVE-2016-3115 | 6.4 | Medium | 2016-03-22 | n/a | Multiple CRLF injection vulnerabilities in session.c in sshd in OpenSSH before 7.2p2 allow remote authenticated users to bypass intended shell-command restrictions via crafted X11 forwarding data, related to the (1) do_authenticated1 and (2) session_x11_req functions. |
| CVE-2016-10011 | 6.2 | Medium | 2017-01-05 | n/a | authfile.c in sshd in OpenSSH before 7.4 does not properly consider the effects of realloc on buffer contents, which might allow local users to obtain sensitive private-key information by leveraging access to a privilege-separated child process. |
| CVE-2016-6210 | 5.9 | Medium | 2017-02-13 | n/a | sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the username does not exist, which allows remote attackers to enumerate users by leveraging the timing difference between responses when a large password is provided. |
| CVE-2019-6111 | 5.9 | Medium | 2019-01-31 | n/a | An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the scp client target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example, to overwrite the .ssh/authorized_keys file). |
| CVE-2023-48795 | 5.9 | Medium | 2023-12-18 | 9.6 | The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in chacha20-poly1305@openssh.com and (if CBC is used) the -etm@openssh.com MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, golang.org/x/crypto before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD before 1.3.8b (and before 1.3.9rc2), ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2 6401, LANCOM LCOS and LANconfig, FileZilla before 3.66.4, Nova before 11.8, PKIX-SSH before 14.4, SecureCRT before 9.4.3, Transmit5 before 5.10.4, Win32-OpenSSH before 9.5.0.0p1-Beta, WinSCP before 6.2.2, Bitvise SSH Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through 0.76.1.13, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust. |
| CVE-2026-59999 | 5.9 | Medium | 2026-07-08 | 10.4 | In sshd in OpenSSH before 10.4, DisableForwarding=yes was supposed to take precedence over PermitTunnel=yes, but did not. |
| CVE-2011-4327 | 5.5 | Medium | 2014-02-03 | n/a | ssh-keysign.c in ssh-keysign in OpenSSH before 5.8p2 on certain platforms executes ssh-rand-helper with unintended open file descriptors, which allows local users to obtain sensitive key information via the ptrace system call. |
| CVE-2016-20012 | 5.3 | Medium | 2021-09-15 | n/a | OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product |
| CVE-2017-15906 | 5.3 | Medium | 2017-10-26 | 7.6 | The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows attackers to create zero-length files. |
| CVE-2018-15473 | 5.3 | Medium | 2018-08-17 | n/a | OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c. |
| CVE-2018-20685 | 5.3 | Medium | 2019-01-10 | n/a | In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact is modifying the permissions of the target directory on the client side. |
| CVE-2026-59998 | 4.8 | Medium | 2026-07-08 | 10.4 | sshd in OpenSSH before 10.4 has an undocumented security-relevant behavior: GSSAPIStrictAcceptorCheck has no value if the server is in Windows Active Directory. |
| CVE-2026-73282 | 4.8 | Medium | 2026-08-11 | 10.5 | In ssh in OpenSSH before 10.5, a use-after-free for realloc data can occur if a certain pair of remote-forwarding operations are concurrent. |
| CVE-2015-5352 | 4.3 | Medium | 2015-08-03 | n/a | The x11_open_helper function in channels.c in ssh in OpenSSH before 6.9, when ForwardX11Trusted mode is not used, lacks a check of the refusal deadline for X connections, which makes it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window. |
| CVE-2014-2532 | 4.2 | Medium | 2014-03-18 | n/a | sshd in OpenSSH before 6.6 does not properly support wildcards on AcceptEnv lines in sshd_config, which allows remote attackers to bypass intended environment restrictions by using a substring located before a wildcard character. |
| CVE-2026-106552 | 4.2 | Medium | 2026-10-06 | 10.6 | In sftp in OpenSSH before 10.6, a server can trigger directory traversal (causing files to be written to unintended locations) during a recursive copy operation. |
| CVE-2026-35414 | 4.2 | Medium | 2026-04-02 | 10.3 | OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters. |
| CVE-2026-59995 | 4.2 | Medium | 2026-07-08 | 10.4 | sftp in OpenSSH before 10.4 does not properly constrain the location of downloaded files when "sftp server:/path ." is used with an attacker-controlled server. |
| CVE-2026-59996 | 4.2 | Medium | 2026-07-08 | 10.4 | scp in OpenSSH before 10.4 may place a file in the parent directory of an intended directory when the copy occurs between two remote destinations. |
| CVE-2026-59997 | 4.2 | Medium | 2026-07-08 | 10.4 | internal-sftp in sshd in OpenSSH before 10.4 recognizes only the first 9 command-line arguments, which can be important if a later command-line argument would have helped to ensure the intended security properties of an SFTP connection. |
| CVE-2010-4755 | 4.0 | Medium | 2011-03-02 | n/a | The (1) remote_glob function in sftp-glob.c and the (2) process_put function in sftp.c in OpenSSH 5.8 and earlier, as used in FreeBSD 7.3 and 8.1, NetBSD 5.0.2, OpenBSD 4.7, and other products, allow remote authenticated users to cause a denial of service (CPU and memory consumption) via crafted glob expressions that do not match any pathnames, as demonstrated by glob expressions in SSH_FXP_STAT requests to an sftp daemon, a different vulnerability than CVE-2010-2632. |
| CVE-2021-36368 | 3.7 | Low | 2022-03-13 | 8.9 | An issue was discovered in OpenSSH before 8.9. If a client is using public-key authentication with agent forwarding but without -oLogLevel=verbose, and an attacker has silently modified the server to support the None authentication option, then the user cannot determine whether FIDO authentication is going to confirm that the user wishes to connect to that server, or that the user wishes to allow that server to connect to a different server on the user's behalf. NOTE: the vendor's position is "this is not an authentication bypass, since nothing is being bypassed. |
| CVE-2026-106582 | 3.7 | Low | 2026-10-06 | 10.6 | In sshd and ssh in OpenSSH before 10.6, an LZ77 dictionary coder can be used even though this is contraindicated by the arXiv 2609.07709 "Crossing the Streams" findings. |
| CVE-2026-60000 | 3.7 | Low | 2026-07-08 | 10.4 | sshd in OpenSSH before 10.4 allows remote attackers to cause a denial of service (resource consumption from excessive authentication attempts) because MaxAuthTries was mishandled for GSSAPIAuthentication. |
| CVE-2026-106587 | 3.6 | Low | 2026-10-06 | 10.6 | In sshd in OpenSSH before 10.6, the value "none" for a configuration option is sometimes interpreted as a filename but was intended to mean that a feature is disabled. |
| CVE-2011-5000 | 3.5 | Low | 2012-04-05 | n/a | The ssh_gssapi_parse_ename function in gss-serv.c in OpenSSH 5.8 and earlier, when gssapi-with-mic authentication is enabled, allows remote authenticated users to cause a denial of service (memory consumption) via a large value in a certain length field. NOTE: there may be limited scenarios in which this issue is relevant. |
| CVE-2026-73281 | 3.5 | Low | 2026-08-11 | 10.5 | In ssh-agent in OpenSSH before 10.5, some operations can occur remotely but were intended to occur only locally, including operations that add tokens or use keys. This is caused by misinteraction between agent locking and the session-bind@openssh.com extension. |
| CVE-2026-35387 | 3.1 | Low | 2026-04-02 | 10.3 | OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms. |
| CVE-2026-106583 | 2.5 | Low | 2026-10-07 | 10.6 | In ssh in OpenSSH before 10.6, a $ or \ character can occur in a command-line username, leading to injection. |
| CVE-2026-106584 | 2.5 | Low | 2026-10-06 | 10.6 | In ssh-keygen in OpenSSH before 10.6, certificates could have incorrect expiration times because of Daylight Saving mishandling. There can be a slightly more severe effect on users in certain Antarctic locations. |
| CVE-2026-106586 | 2.5 | Low | 2026-10-06 | 10.6 | In sshd in OpenSSH before 10.6, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not, a different vulnerability than CVE-2026-73283. |
| CVE-2026-35388 | 2.5 | Low | 2026-04-02 | 10.3 | OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions. |
| CVE-2026-73283 | 2.5 | Low | 2026-08-11 | 10.5 | In sshd in OpenSSH before 10.5, the restrict keyword (in authorized_keys) was supposed to be applicable to tunnel forwarding but was not. |
| CVE-2026-106553 | 2.2 | Low | 2026-10-06 | 10.6 | In sshd in OpenSSH before 10.6, credentials can incorrectly persist after failure of a GSSAPIAuthentication authentication attempt. |
| CVE-2026-106555 | 2.2 | Low | 2026-10-06 | 10.6 | In sshd in OpenSSH before 10.6, GSSAPIAuthentication authentication state can incorrectly be persisted across authentication attempts. |