Vulnary
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Critical· 9.1official fix available

CVE-2026-6100

A use‑after‑free bug in Python’s built‑in decompression modules can be triggered when a MemoryError occurs and the same decompressor object is reused. The bug allows an attacker to corrupt memory and potentially execute arbitrary code. The issue is fixed in newer Python releases.

publishedApr 13, 2026
last modifiedAug 5, 2026
sourcesNVD
severity · cvss
9.1
critical · how bad it is
exploitation · epss
<1%
44th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Sep 4, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Python applications that reuse lzma.LZMADecompressor, bz2.BZ2Decompressor, or gzip.GzipFile objects across multiple decompressions after a MemoryError.

02

Real-world impact

An attacker could cause a crash or gain code execution by forcing a MemoryError and reusing the decompressor, especially in memory‑constrained environments.

03

Why this severity

The CVSS score reflects the high impact on confidentiality and integrity, the high attack complexity, and the lack of user interaction required.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade Python to a version that includes the fix for CVE-2026-6100.
  2. 02Restart any services or applications that use Python.

NVD-referenced vendor advisory

05

Timeline

  1. Apr 13, 2026 · Apr 13, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Aug 5, 2026 · 2h ago
    Advisory updated
    The NVD record was last revised.
  3. Aug 5, 2026 · 25m ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityHigh
Attack requirementsPresent
Privileges requiredNone
User interactionNone needed
Confidentiality impactHigh
Integrity impactHigh
Availability impactNone
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →