id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
5910	python CVE-2026-6100	Joe Locash	lfs-book	"{{{
There is a CRITICAL severity vulnerability affecting CPython.

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.

The vulnerability is only present if the program re-uses decompressor
instances across multiple decompression calls even after a MemoryError is
raised during decompression. Using the helper functions to one-shot
decompress data such as lzma.decompress(), bz2.decompress(),
gzip.decompress(), and zlib.decompress() are not affected as a new
decompressor instance is created for each call. If the decompressor
instance is not re-used after an error condition, this usage is similarly
not vulnerable.

Please see the linked CVE ID for the latest information on affected
versions:

    https://www.cve.org/CVERecord?id=CVE-2026-6100
    https://github.com/python/cpython/pull/148396
}}}

Source: https://mail.python.org/archives/list/security-announce@python.org/thread/HTWB2Z6KT5QQX4RYEZAFININDHNOSIF3/
"	enhancement	new	highest	13.1	Book	git	normal