Python 3.6, end of life since 23 December 2021
Python 3.6.15 vulnerabilities
Python 3.6.15 is the last release of the 3.6 branch, end of life since 23 December 2021. The US National Vulnerability Database lists 28 vulnerabilities for this version, 2 of them critical. The Python project fixes flaws only in supported versions. Distributions backport those fixes while they are supported and stop at end of life.
- 28known vulnerabilities
- 2critical
- 16high
- 0exploited in the wild
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All 28 known vulnerabilities in Python 3.6.15
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-2007-4559 | 9.8 | Critical | 2007-08-28 | 3.6.16 | Directory traversal vulnerability in the (1) extract and (2) extractall functions in the tarfile module in Python allows user-assisted remote attackers to overwrite arbitrary files via a .. (dot dot) sequence in filenames in a TAR archive, a related issue to CVE-2001-1267. |
| CVE-2022-37454 | 9.8 | Critical | 2022-10-21 | 3.7.16 | The Keccak XKCP SHA-3 reference implementation before fdc6fef has an integer overflow and resultant buffer overflow that allows attackers to execute arbitrary code or eliminate expected cryptographic properties. This occurs in the sponge function interface. |
| CVE-2024-9287 | 7.8 | High | 2024-10-22 | 3.9.21 | A vulnerability has been found in the CPython `venv` module and CLI where path names provided when creating a virtual environment were not quoted properly, allowing the creator to inject commands into virtual environment "activation" scripts (ie "source venv/bin/activate"). This means that attacker-controlled virtual environments are able to run commands when the virtual environment is activated. Virtual environments which are not created by an attacker or which aren't activated before being used (ie "./venv/bin/python") are not affected. |
| CVE-2018-20406 | 7.5 | High | 2018-12-23 | 3.7.1 | Modules/_pickle.c in Python before 3.7.1 has an integer overflow via a large LONG_BINPUT value that is mishandled during a "resize to twice the size" attempt. This issue might cause memory exhaustion, but is only relevant if the pickle format is used for serializing tens or hundreds of gigabytes of data. This issue is fixed in: v3.4.10, v3.4.10rc1; v3.5.10, v3.5.10rc1, v3.5.7, v3.5.7rc1, v3.5.8, v3.5.8rc1, v3.5.8rc2, v3.5.9; v3.6.10, v3.6.10rc1, v3.6.11, v3.6.11rc1, v3.6.12, v3.6.7, v3.6.7rc1, v3.6.7rc2, v3.6.8, v3.6.8rc1, v3.6.9, v3.6.9rc1; v3.7.1, v3.7.1rc1, v3.7.1rc2, v3.7.2, v3.7.2rc1, v3.7.3, v3.7.3rc1, v3.7.4, v3.7.4rc1, v3.7.4rc2, v3.7.5, v3.7.5rc1, v3.7.6, v3.7.6rc1, v3.7.7, v3.7.7rc1, v3.7.8, v3.7.8rc1, v3.7.9. |
| CVE-2019-9674 | 7.5 | High | 2020-02-04 | n/a | Lib/zipfile.py in Python through 3.7.2 allows remote attackers to cause a denial of service (resource consumption) via a ZIP bomb. |
| CVE-2022-45061 | 7.5 | High | 2022-11-09 | n/a | An issue was discovered in Python before 3.11.1. An unnecessary quadratic algorithm exists in one path when processing some inputs to the IDNA (RFC 3490) decoder, such that a crafted, unreasonably long name being presented to the decoder could lead to a CPU denial of service. Hostnames are often supplied by remote servers that could be controlled by a malicious actor; in such a scenario, they could trigger excessive CPU consumption on the client attempting to make use of an attacker-supplied supposed hostname. For example, the attack payload could be placed in the Location header of an HTTP response with status code 302. A fix is planned in 3.11.1, 3.10.9, 3.9.16, 3.8.16, and 3.7.16. |
| CVE-2023-24329 | 7.5 | High | 2023-02-17 | 3.7.17 | An issue in the urllib.parse component of Python before 3.11.4 allows attackers to bypass blocklisting methods by supplying a URL that starts with blank characters. |
| CVE-2023-36632 | 7.5 | High | 2023-06-25 | n/a | The legacy email.utils.parseaddr function in Python through 3.11.4 allows attackers to trigger "RecursionError: maximum recursion depth exceeded while calling a Python object" via a crafted argument. This argument is plausibly an untrusted value from an application's input data that was supposed to contain a name and an e-mail address. NOTE: email.utils.parseaddr is categorized as a Legacy API in the documentation of the Python email package. Applications should instead use the email.parser.BytesParser or email.parser.Parser class. NOTE: the vendor's perspective is that this is neither a vulnerability nor a bug. The email package is intended to have size limits and to throw an exception when limits are exceeded; they were exceeded by the example demonstration code. |
| CVE-2024-6232 | 7.5 | High | 2024-09-03 | 3.8.20 | There is a MEDIUM severity vulnerability affecting CPython. Regular expressions that allowed excessive backtracking during tarfile.TarFile header parsing are vulnerable to ReDoS via specifically-crafted tar archives. |
| CVE-2024-7592 | 7.5 | High | 2024-08-19 | 3.8.20 | There is a LOW severity vulnerability affecting CPython, specifically the 'http.cookies' standard library module. When parsing cookies that contained backslashes for quoted characters in the cookie value, the parser would use an algorithm with quadratic complexity, resulting in excess CPU resources being used while parsing the value. |
| CVE-2025-13836 | 7.5 | High | 2025-12-01 | 3.10.20 | When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS. |
| CVE-2026-15308 | 7.5 | High | 2026-07-09 | 3.10.21 | The incremental HTML parser (html.parser.HTMLParser) allows for CPU denial-of-service through repeated unterminated markup declarations when processing uncontrolled data. |
| CVE-2026-3087 | 7.5 | High | 2026-04-27 | n/a | If `shutil.unpack_archive()` is given a ZIP archive with an absolute Windows path containing a drive (`C:\\...`) then the archive will be extracted outside the target directory which is different than other operating systems. Only Windows is affected by this vulnerability. |
| CVE-2026-3644 | 7.5 | High | 2026-03-16 | 3.13.13 | The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output(). |
| CVE-2026-4224 | 7.5 | High | 2026-03-16 | 3.10.0 | When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs. |
| CVE-2026-7210 | 7.5 | High | 2026-05-11 | 3.13.14 | `xml.parsers.expat` and `xml.etree.ElementTree` use insufficient entropy for Expat hash-flooding protection, which allows a crafted XML document to trigger hash flooding.\r\n\r\nFully mitigating this vulnerability requires both updating libexpat to 2.8.0 or later and applying this patch. |
| CVE-2021-28861 | 7.4 | High | 2022-08-23 | 3.7.14 | Python 3.x through 3.10 has an open redirection vulnerability in lib/http/server.py due to no protection against multiple (/) at the beginning of URI path which may leads to information disclosure. NOTE: this is disputed by a third party because the http.server.html documentation page states "Warning: http.server is not recommended for production. It only implements basic security checks." |
| CVE-2022-26488 | 7.0 | High | 2022-03-10 | n/a | In Python before 3.10.3 on Windows, local users can gain privileges because the search path is inadequately secured. The installer may allow a local attacker to add user-writable directories to the system search path. To exploit, an administrator must have installed Python for all users and enabled PATH entries. A non-administrative user can trigger a repair that incorrectly adds user-writable paths into PATH, enabling search-path hijacking of other users and system services. This affects Python (CPython) through 3.7.12, 3.8.x through 3.8.12, 3.9.x through 3.9.10, and 3.10.x through 3.10.2. |
| CVE-2026-6019 | 6.1 | Medium | 2026-04-22 | 3.13.14 | http.cookies.Morsel.js_output() returns an inline <script> snippet and only escapes " for JavaScript string context. It does not neutralize the HTML parser-sensitive sequence </script> inside the generated script element. Mitigation base64-encodes the cookie value to disallow escaping using cookie value. |
| CVE-2025-13837 | 5.5 | Medium | 2025-12-01 | 3.13.10 | When loading a plist file, the plistlib module reads data in size specified by the file itself, meaning a malicious file can cause OOM and DoS issues |
| CVE-2025-6075 | 5.5 | Medium | 2025-10-31 | 3.9.0 | If the value passed to os.path.expandvars() is user-controlled a performance degradation is possible when expanding environment variables. |
| CVE-2026-0864 | 5.5 | Medium | 2026-06-23 | 3.10.21 | When using the "configparser" module to write configuration files containing multi-line text values with carriage return characters (\r) the resulting file could be injected with unexpected keys and values if the attacker controls the written value. |
| CVE-2023-27043 | 5.3 | Medium | 2023-04-19 | 3.8.20 | The email module of Python through 3.11.3 incorrectly parses e-mail addresses that contain a special character. The wrong portion of an RFC2822 header is identified as the value of the addr-spec. In some applications, an attacker can bypass a protection mechanism in which application access is granted only after verifying receipt of e-mail to a specific domain (e.g., only @company.example.com addresses may be used for signup). This occurs in email/_parseaddr.py in recent versions of Python. |
| CVE-2023-40217 | 5.3 | Medium | 2023-08-25 | 3.8.18 | An issue was discovered in Python before 3.8.18, 3.9.x before 3.9.18, 3.10.x before 3.10.13, and 3.11.x before 3.11.5. It primarily affects servers (such as HTTP servers) that use TLS client authentication. If a TLS server-side socket is created, receives data into the socket buffer, and then is closed quickly, there is a brief window where the SSLSocket instance will detect the socket as "not connected" and won't initiate a handshake, but buffered data will still be readable from the socket buffer. This data will not be authenticated if the server-side TLS peer is expecting client certificate authentication, and is indistinguishable from valid TLS stream data. Data is limited in size to the amount that will fit in the buffer. (The TLS connection cannot directly be used for data exfiltration because the vulnerable code path requires that the connection be closed on initialization of the SSLSocket.) |
| CVE-2025-12084 | 5.3 | Medium | 2025-12-03 | 3.13.11 | When building nested elements using xml.dom.minidom methods such as appendChild() that have a dependency on _clear_id_cache() the algorithm is quadratic. Availability can be impacted when building excessively nested documents. |
| CVE-2025-12781 | 5.3 | Medium | 2026-01-21 | 3.13.10 | When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode() functions in the "base64" module the characters "+/" will always be accepted, regardless of the value of "altchars" parameter, typically used to establish an "alternative base64 alphabet" such as the URL safe alphabet. This behavior matches what is recommended in earlier base64 RFCs, but newer RFCs now recommend either dropping characters outside the specified base64 alphabet or raising an error. The old behavior has the possibility of causing data integrity issues. This behavior can only be insecure if your application uses an alternate base64 alphabet (without "+/"). If your application does not use the "altchars" parameter or the urlsafe_b64decode() function, then your application does not use an alternative base64 alphabet. The attached patches DOES NOT make the base64-decode behavior raise an error, as this would be a change in behavior and break existing programs. Instead, the patch deprecates the behavior which will be replaced with the newly recommended behavior in a future version of Python. Users are recommended to mitigate by verifying user-controlled inputs match the base64 alphabet they are expecting or verify that their application would not be affected if the b64decode() functions accepted "+" or "/" outside of altchars. |
| CVE-2025-13462 | 3.3 | Low | 2026-03-12 | 3.13.13 | The "tarfile" module would still apply normalization of AREGTYPE (\x00) blocks to DIRTYPE, even while processing a multi-block member such as GNUTYPE_LONGNAME or GNUTYPE_LONGLINK. This could result in a crafted tar archive being misinterpreted by the tarfile module compared to other implementations. |
| CVE-2026-4519 | 3.3 | Low | 2026-03-20 | 3.13.13 | The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open(). |