Low severity · published Aug 25, 2026
CVE-2026-15310
zipfile: bzip2/LZMA/Zstandard members decompress without a max_length bound, defeating chunked-read memory limits
2.1
CVSS
0.5%
EPSS
No
On KEV
Description
When decompressing crafted zip files using the bzip/LZMA/Zstandard
compressions, Python could use an attacker-controlled size to
pre-allocate memory, possibly resulting in memory exhaustion.
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 44% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CP
CPython · Python Software Foundation
before 3.10.22; 3.11.0 before 3.11.17; 3.12.0 before 3.12.15; 3.13.0 before 3.13.16; 3.14.0 before 3.14.8; 3.15.0a1 before 3.15.0rc2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-15310
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-15310
patch
https://github.com/python/cpython/pull/156003
issue-tracking
https://github.com/python/cpython/issues/156002
vendor-advisory
https://mail.python.org/archives/list/security-announce@python.org/thread/YUHXURX2WZGKGNA4ANYBQS2VZRYQ5JNK/
patch
https://github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4
patch
https://github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8
patch
https://github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89
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