Python Software Foundation Cpython vulnerabilities

CVE-2026-5713 [MEDIUM] CWE-121 CVE-2026-5713: The "profiling.sampling" module (Python 3.15+) and "asyncio introspection capabilities" (3.14+, "pyt The "profiling.sampling" module (Python 3.15+) and "asyncio introspection capabilities" (3.14+, "python -m asyncio ps" and "python -m asyncio pstree") features could be used to read and write addresses in a privileged process if that process connected to a malicious or "infected" Python process via the remote debugging feature. This vulnerability requ

CVE-2026-6100 [CRITICAL] CWE-416 CVE-2026-6100: Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.G Use-after-free (UAF) was possible in the `lzma.LZMADecompressor`, `bz2.BZ2Decompressor`, and `gzip.GzipFile` when a memory allocation fails with a `MemoryError` and the decompression instance is re-used. This scenario can be triggered if the process is under memory pressure. The fix cleans up the dangling pointer in this specific error condition. T

CVE-2026-4786 [HIGH] CWE-77 Incomplete mitigation of CVE-2026-4519, %action expansion for command injection to webbrowser.open() Incomplete mitigation of CVE-2026-4519, %action expansion for command injection to webbrowser.open() Mitgation of CVE-2026-4519 was incomplete. If the URL contained "%action" the mitigation could be bypassed for certain browser types the "webbrowser.open()" API could have commands injected into the underlying shell. See CVE-2026-4519 for details.

CVE-2026-1502 [MEDIUM] CVE-2026-1502: CR/LF bytes were not rejected by HTTP client proxy tunnel headers or host. CR/LF bytes were not rejected by HTTP client proxy tunnel headers or host.

CVE-2026-3446 [MEDIUM] CWE-345 CVE-2026-3446: When calling base64.b64decode() or related functions the decoding process would stop after encounter When calling base64.b64decode() or related functions the decoding process would stop after encountering the first padded quad regardless of whether there was more information to be processed. This can lead to data being accepted which may be processed differently by other implementations. Use "validate=True" to enable stricter processing of base64 dat

CVE-2026-4519 [HIGH] CWE-20 CVE-2026-4519: The webbrowser.open() API would accept leading dashes in the URL which could be handled as command 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().

CVE-2026-3479 [NONE] CWE-22 CVE-2026-3479: DISPUTED: The project has clarified that the documentation was incorrect, and that pkgutil.get_data( DISPUTED: The project has clarified that the documentation was incorrect, and that pkgutil.get_data() has the same security model as open(). The documentation has been updated to clarify this point. There is no vulnerability in the function if following the intended security model. pkgutil.get_data() did not validate the resource argument as documented,

CVE-2026-3644 [MEDIUM] Incomplete control character validation in http.cookies Incomplete control character validation in http.cookies 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 [MEDIUM] CWE-674 CVE-2026-4224: When an Expat parser with a registered ElementDeclHandler parses an inline document type definition 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-2025-13462 [LOW] CWE-20 CVE-2025-13462: The "tarfile" module would still apply normalization of AREGTYPE (\x00) blocks to DIRTYPE, even whil 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-2026-2297 [MEDIUM] CWE-668 CVE-2026-2297: The import hook in CPython that handles legacy *.pyc files (SourcelessFileLoader) is incorrectly han The import hook in CPython that handles legacy *.pyc files (SourcelessFileLoader) is incorrectly handled in FileLoader (a base class) and so does not use io.open_code() to read the .pyc files. sys.audit handlers for this audit event therefore do not fire.

CVE-2026-1299 [MEDIUM] CWE-93 CVE-2026-1299: The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing headers that don't respect email folding rules, the new behavior will reject the incorrectly fol

CVE-2025-12781 [MEDIUM] CWE-704 CVE-2025-12781: When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode() functions in the 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 ear

CVE-2025-15282 [MEDIUM] CWE-93 CVE-2025-15282: User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newli User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.

CVE-2025-15367 [MEDIUM] CWE-77 CVE-2025-15367: The poplib module, when passed a user-controlled command, can have additional commands injected usin The poplib module, when passed a user-controlled command, can have additional commands injected using newlines. Mitigation rejects commands containing control characters.

CVE-2026-0865 [MEDIUM] CWE-74 CVE-2026-0865: User-controlled header names and values containing newlines can allow injecting HTTP headers. User-controlled header names and values containing newlines can allow injecting HTTP headers.

CVE-2025-15366 [MEDIUM] CWE-77 CVE-2025-15366: The imaplib module, when passed a user-controlled command, can have additional commands injected usi The imaplib module, when passed a user-controlled command, can have additional commands injected using newlines. Mitigation rejects commands containing control characters.

CVE-2025-11468 [MEDIUM] CWE-93 CVE-2025-11468: When folding a long comment in an email header containing exclusively unfoldable characters, the par When folding a long comment in an email header containing exclusively unfoldable characters, the parenthesis would not be preserved. This could be used for injecting headers into email messages where addresses are user-controlled and not sanitized.

CVE-2026-0672 [MEDIUM] CWE-93 CVE-2026-0672: When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTT When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters.

CVE-2025-12084 [MEDIUM] CWE-407 CVE-2025-12084: When building nested elements using xml.dom.minidom methods such as appendChild() that have a depend 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.