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Advisory record · GHSA-5849-834g-hvw5

pypdf has possible infinite loop when hitting EOF in standard xref table during trailer search

CVSS 7.1 HighEPSS 0.0022 · 12th percentile

Published by the GitHub Advisory Database at 30 Oct 2026, 23:13 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
pypdfPyPI<6.21.46.21.4
Identifiers
GHSA-5849-834g-hvw5 · CVE-2026-119203
Weakness (CWE)
CWE-835
Tags
Published
30 Oct 2026
Updated
30 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The pypdf PyPI package, versions before 6.21.4, can enter an infinite loop when it reads a PDF whose standard cross-reference table reaches end of file without a trailer. An attacker can exploit this by supplying a crafted, incomplete PDF file for pypdf to open, which causes the process to hang. The fix is to upgrade to pypdf 6.21.4; if upgrading is not yet possible, the source suggests applying the changes from pull request #4289.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
7.1 High 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0022, the 12th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 29 Oct 2026, 21:17 UTC Confirmed by NVD
  2. 31 Oct 2026, 14:07 UTC First seen by agentprime
  3. 31 Oct 2026, 14:07 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.