GitHub Advisoryadvisory · PyPI

GHSA-jw7q-gvrg-4vj3 pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)

HIGH Published 2026-10-01 Modified 2026-10-01 Official page ↗
Aliases
CVE-2026-102997
Ecosystem
PyPI
Packages
pypdf
Severity
High
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weaknesses
CWE-400, CWE-407
Reviewed
2026-10-01

Affected packages

• PyPI pypdf: < 6.18.1 → fixed in 6.18.1

Description

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a partially malformed `/FlateDecode` stream, where the byte-by-byte decompression is used. Patches This has been fixed in pypdf==6.18.1. Workarounds If you cannot upgrade yet, consider applying the changes from PR #4073.

Related

Alias · CVE (1)

  • CVE-2026-102997 pypdf is a free and open-source pure-python PDF library. vulnerability

Weakness · CWE (2)

  • CWE-400 Uncontrolled Resource Consumption weakness
  • CWE-407 Inefficient Algorithmic Complexity weakness

References