---
id: CVE-2026-15310
title: |-
  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.
summary: |-
  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.
severity: low
cvss: 2.1
cvssVector: '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'
cwe:
  - CWE-400
vendor: Python Software Foundation
product: CPython
affected:
  - CPython < 3.15.0rc2
published: '2026-08-25'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T01:16:43.803'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-15310'
references:
  - url: >-
      https://github.com/python/cpython/commit/1b424c0178a01e155fd0267dc28a8fc1159b33a8
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/31980e84b9a708424a0a1dfecde3fc991e313f89
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/9d167992b59cf5e23c66b9ed742b13f5925f7d70
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/e2311cfb3dd518f008f312fe0631f4f7490d237a
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/f507e6946a3194e83e1d7b8ee6e14567175e46de
    label: cna@python.org
  - url: >-
      https://github.com/python/cpython/commit/f897dbf2f36a5935700b7c2d94d4681d2136b7d4
    label: cna@python.org
  - url: 'https://github.com/python/cpython/issues/156002'
    label: cna@python.org
  - url: 'https://github.com/python/cpython/pull/156003'
    label: cna@python.org
  - url: >-
      https://mail.python.org/archives/list/security-announce@python.org/thread/YUHXURX2WZGKGNA4ANYBQS2VZRYQ5JNK/
    label: cna@python.org
tags:
  - nvd
  - cve.org
epss: 0.005
epssPercentile: 0.40177
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-25T15:34:06.442859Z'
cvssSource: cna
ingestedAt: '2026-09-11T16:45:47.927Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.