- Python 3.12.13 final
- Release date: 2026-03-03
- Security
- gh-144125: BytesGenerator will now refuse to serialize
(write) headers that are unsafely folded or delimited; see
verify_generated_headers. (Contributed by Bas Bloemsaat and
Petr Viktorin in gh-121650).
- gh-143935: Fixed a bug in the folding of comments when
flattening an email message using a modern email policy.
Comments consisting of a very long sequence of non-foldable
characters could trigger a forced line wrap that omitted
the required leading space on the continuation line,
causing the remainder of the comment to be interpreted as
a new header field. This enabled header injection with
carefully crafted inputs (bsc#1257029 CVE-2025-11468).
- gh-143925: Reject control characters in data: URL media
types (bsc#1257046, CVE-2025-15282).
- gh-143919: Reject control characters in http.cookies.Morsel
fields and values (bsc#1257031, CVE-2026-0672).
- gh-143916: Reject C0 control characters within
wsgiref.headers.Headers fields, values, and parameters
(bsc#1257042, CVE-2026-0865).
- gh-142145: Remove quadratic behavior in xml.minidom node ID
cache clearing. In order to do this without breaking
existing users, we also add the ownerDocument attribute to
xml.dom.minidom elements and attributes created by directly
instantiating the Element or Attr class. Note that this way
of creating nodes is not supported; creator functions like
xml.dom.Document.documentElement() should be used instead
(bsc#1254997, CVE-2025-12084).
- gh-137836: Add support of the “plaintext” element, RAWTEXT
elements “xmp”, “iframe”, “noembed” and “noframes”, and
optionally RAWTEXT element “noscript” in
html.parser.HTMLParser.
- gh-136063: email.message: ensure linear complexity for
legacy HTTP parameters parsing. Patch by Bénédikt Tran.
- gh-136065: Fix quadratic complexity in
os.path.expandvars() (bsc#1252974, CVE-2025-6075).
- gh-119451: Fix a potential memory denial of service in the
http.client module. When connecting to a malicious server,
it could cause an arbitrary amount of memory to be
allocated. This could have led to symptoms including
a MemoryError, swapping, out of memory (OOM) killed
processes or containers, or even system crashes
(CVE-2025-13836, bsc#1254400).
- gh-119452: Fix a potential memory denial of service in the
http.server module. When a malicious user is connected to
the CGI server on Windows, it could cause an arbitrary
amount of memory to be allocated. This could have led to
symptoms including a MemoryError, swapping, out of memory
(OOM) killed processes or containers, or even system
crashes.
- gh-119342: Fix a potential memory denial of service in the
plistlib module. When reading a Plist file received from
untrusted source, it could cause an arbitrary amount of
memory to be allocated. This could have led to symptoms
including a MemoryError, swapping, out of memory (OOM)
killed processes or containers, or even system crashes
(bsc#1254401, CVE-2025-13837).
- Library
- gh-144833: Fixed a use-after-free in ssl when SSL_new()
returns NULL in newPySSLSocket(). The error was reported
via a dangling pointer after the object had already been
freed.
- gh-144363: Update bundled libexpat to 2.7.4
- gh-90949: Add SetAllocTrackerActivationThreshold() and
SetAllocTrackerMaximumAmplification() to xmlparser objects
to prevent use of disproportional amounts of dynamic memory
from within an Expat parser. Patch by Bénédikt Tran.
Remove upstreamed patches:
- CVE-2025-11468-email-hdr-fold-comment.patch
- CVE-2025-12084-minidom-quad-search.patch
- CVE-2025-13836-http-resp-cont-len.patch
- CVE-2025-13837-plistlib-mailicious-length.patch
- CVE-2025-6075-expandvars-perf-degrad.patch
- CVE-2026-0672-http-hdr-inject-cookie-Morsel.patch
- CVE-2026-0865-wsgiref-ctrl-chars.patch
- CVE-2025-15282-urllib-ctrl-chars.patch
CVE-2025-11468: to preserve parens when folding comments.
(bsc#1257029, gh#python/cpython#143935)
CVE-2025-11468-email-hdr-fold-comment.patch
CVE-2025-12781: fix decoding with non-standard Base64 alphabet
(bsc#1257108, gh#python/cpython#125346)
CVE-2025-12781-b64decode-alt-chars.patch
CVE-2026-0672: rejects control characters in http cookies.
(bsc#1257031, gh#python/cpython#143919)
CVE-2026-0672-http-hdr-inject-cookie-Morsel.patch
CVE-2026-0865: rejecting control characters in
wsgiref.headers.Headers, which could be abused for injecting
false HTTP headers. (bsc#1257042, gh#python/cpython#143916)
CVE-2026-0865-wsgiref-ctrl-chars.patch
CVE-2025-15366: basically the same as the previous patch for
IMAP protocol. (bsc#1257044, gh#python/cpython#143921)
CVE-2025-15366-imap-ctrl-chars.patch
CVE-2025-15282: basically the same as the previous patch for
urllib library. (bsc#1257046, gh#python/cpython#143925)
CVE-2025-15282-urllib-ctrl-chars.patch
CVE-2025-15367: basically the same as the previous patch for
poplib library. (bsc#1257041, gh#python/cpython#143923)
CVE-2025-15367-poplib-ctrl-chars.patch
CVE-2025-13836: to prevent reading an HTTP response from
Content-Length per default as the length. (bsc#1254400,
gh#python/cpython#119451)
CVE-2025-13836-http-resp-cont-len.patch
CVE-2025-12084: prevent quadratic behavior in node ID cache
clearing. (bsc#1254997, gh#python/cpython#142145)
CVE-2025-12084-minidom-quad-search.patch
CVE-2025-13837: protect against OOM when loading malicious
content. (bsc#1254401, gh#python/cpython#119342)
CVE-2025-13837-plistlib-mailicious-length.patch
- gh-99242: os.getloadavg() may throw OSError when running
regression tests under certain conditions (e.g. chroot).
This error is now caught and ignored, since reporting load
average is optional.
- gh-121160: Add a test for readline.set_history_length().
Note that this test may fail on readline libraries.
- gh-121200: Fix test_expanduser_pwd2() of test_posixpath.
Call getpwnam() to get pw_dir, since it can be different
than getpwall() pw_dir. Patch by Victor Stinner.
- gh-121188: When creating the JUnit XML file, regrtest now
escapes characters which are invalid in XML, such as the
chr(27) control character used in ANSI escape sequences.
Patch by Victor Stinner.
- CVE-2026-1299 and CVE-2024-6923: email headers with
embedded newlines are now quoted on output. The generator
will now refuse to serialize (write) headers that are
unsafely folded or delimited; see verify_generated_headers.
(Contributed by Bas Bloemsaat and Petr Viktorin in
bsc#1228780, gh-121650; bsc#1257181, gh-121650).
- gh-120495: Fix incorrect exception handling in Tab Nanny.
Patch by Wulian233.
would produce incorrect results if type parameters in
a class scope were overridden by assignments in a class
scope and from __future__ import annotations semantics were
- gh-81936: help() and showtopic() methods now respect
a configured output argument to pydoc.Helper and not use
the pager in such cases. Patch by Enrico Tröger.
- gh-119577: The DeprecationWarning emitted when testing the
truth value of an xml.etree.ElementTree.Element now
- gh-121871: Documentation HTML varies from timestamp. Patch
by Bernhard M. Wiedemann (bsc#1227999).
- gh-122029: Emit c_call events in sys.setprofile() when
a PyMethodObject pointing to a PyCFunction is called.
modification of a list object, where one thread assigns
a slice and another clears it.
bytes and bytearray objects when using protocol version 5.
Patch by Bénédikt Tran.
- Add CVE-2025-13836-http-resp-cont-len.patch (bsc#1254400,
CVE-2025-13836) to prevent reading an HTTP response from
a server, if no read amount is specified, with using
Content-Length per default as the length.
- Add CVE-2025-12084-minidom-quad-search.patch prevent quadratic
behavior in node ID cache clearing (CVE-2025-12084,
bsc#1254997).
- Add CVE-2025-13837-plistlib-mailicious-length.patch protect
against OOM when loading malicious content (CVE-2025-13837,
bsc#1254401).
Fix readline history truncation when length is reduced
The `readline.set_history_length()` function did not previously
truncate the in-memory history when the new length was set to
a value smaller than the current number of history items. This
could lead to unexpected behavior where `get_history_length()`
would still report the old length and writing the history to a
file would write more entries than the new limit.
This patch modifies `set_history_length()` to explicitly
remove the oldest history entries using `remove_history()`
when the length is decreased, ensuring the in-memory history
is correctly truncated to the new limit. This brings the
function's behavior in line with expectations and fixes
failures in `test_write_read_limited_history`.
- Tools/Demos
- gh-139330: SBOM generation tool didn’t cross-check the version
and checksum values against the Modules/expat/refresh.sh script,
leading to the values becoming out-of-date during routine
updates.
- Security
- gh-139700: Check consistency of the zip64 end of central
directory record. Support records with “zip64 extensible data”
if there are no bytes prepended to the ZIP file.
- gh-139400: xml.parsers.expat: Make sure that parent Expat
parsers are only garbage-collected once they are no longer
referenced by subparsers created by
ExternalEntityParserCreate(). Patch by Sebastian Pipping.
- gh-135661: Fix parsing start and end tags in
html.parser.HTMLParser according to the HTML5 standard.
* Whitespaces no longer accepted between </ and the tag name.
E.g. </ script> does not end the script section.
* Vertical tabulation (\v) and non-ASCII whitespaces no longer
recognized as whitespaces. The only whitespaces are \t\n\r\f
and space.
* Null character (U+0000) no longer ends the tag name.
* Attributes and slashes after the tag name in end tags are now
ignored, instead of terminating after the first > in quoted
attribute value. E.g. </script/foo=">"/>.
* Multiple slashes and whitespaces between the last attribute
and closing > are now ignored in both start and end tags. E.g.
<a foo=bar/ //>.
* Multiple = between attribute name and value are no longer
collapsed. E.g. <a foo==bar> produces attribute “foo” with
OBS-URL: https://build.opensuse.org/package/show/devel:languages:python:Factory/python312?expand=0&rev=162
