Low 2.1Published Aug 25, 2026

CVE-2026-15310zipfile: bzip2/LZMA/Zstandard members decompress without a max_length bound, defeating chunked-read memory limits

Updated under an hour ago (Oct 27, 2026, 11:00 AM ET)

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It affects Python Software Foundation CPython. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for Python Software Foundation CPython

Exploited in the last 30 days

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.

CVSS: 2.1 LOW (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: PSF
NVD analysis: Awaiting Analysis
Record last updated: Oct 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Python Software Foundation CPython python_software_foundation:cpython (from the name)	before 3.10.22; from 3.11.0 before 3.11.17; from 3.12.0 before 3.12.15; from 3.13.0 before 3.13.16; from 3.14.0 before 3.14.8; from 3.15.0a1 before 3.15.0rc2	CNA record

References

References

https://github.com/python/cpython/pull/156003	patch
https://github.com/python/cpython/issues/156002	issue-tracking
https://mail.python.org/archives/list/security-announce@python.org/thread/YUHXURX2WZGKGNA4ANYBQS2VZRYQ5JNK/	vendor-advisory
https://github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4	patch
https://github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8	patch
https://github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89	patch
https://github.com/python/cpython/commit/e2311cfb3dd518f008f312fe0631f4f7490d237a	patch
https://github.com/python/cpython/commit/f507e6946a3194e83e1d7b8ee6e14567175e46de	patch
https://github.com/python/cpython/commit/9d167992b59cf5e23c66b9ed742b13f5925f7d70	patch
https://github.com/python/cpython/commit/dcdd406ddbfc4cb29b24c3df17cbabe21d316ce1	patch
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.