CVE-2026-15310
zipfile: bzip2/LZMA/Zstandard members decompress without a max_length bound, defeating chunked-read memory limits
At a glance
- Severity
- LOW 2.1
- EPSS
- EPSS 0.53 % · percentile 44 (2026-10-27)
- State
- PUBLISHED
- Published
- Updated
- Assigner
- PSF
- NVD status
- Awaiting Analysis
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.
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | LOW 2.1 | 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 | PSF |
| CVSS 4.0 | LOW 2.1 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cna@python.org (Secondary) |
Weaknesses (CWE)
European references
- ENISA EUVD · EUVD-2026-65519
- GCVE · GCVE-0-2026-15310
CERT-FR advisories
- CERTFR-2026-AVI-1249 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1087 — Vulnérabilité dans CPython · cert.ssi.gouv.fr
Affected products
| Product | Versions |
|---|---|
| Python Software Foundation · CPython | affected 0 < 3.10.22 ; affected 3.11.0 < 3.11.17 ; affected 3.12.0 < 3.12.15 ; affected 3.13.0 < 3.13.16 ; affected 3.14.0 < 3.14.8 ; affected 3.15.0a1 < 3.15.0rc2 |
References
- https://github.com/python/cpython/pull/156003
- https://github.com/python/cpython/issues/156002
- https://mail.python.org/archives/list/security-announce@python.org/thread/YUHXURX2WZGKGNA4ANYBQS2VZRYQ5JNK/
- https://github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4
- https://github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8
- https://github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89
- https://github.com/python/cpython/commit/e2311cfb3dd518f008f312fe0631f4f7490d237a
- https://github.com/python/cpython/commit/f507e6946a3194e83e1d7b8ee6e14567175e46de
- https://github.com/python/cpython/commit/9d167992b59cf5e23c66b9ed742b13f5925f7d70
- https://github.com/python/cpython/commit/dcdd406ddbfc4cb29b24c3df17cbabe21d316ce1
- https://github.com/python/cpython/commit/09a2e7e6678b4f65449e7ad8f112c48f944591e2
- https://github.com/python/cpython/commit/6257029de42ef89b67f3d20137de87d43e197530
- https://github.com/python/cpython/commit/c2bfbcdd1a11690507a10bc0998f95b8dc6b6fac
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |