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Advisory record · GHSA-248m-82v9-q6g6

pypdf: Possible long runtimes for zero-only width values in cross-reference streamsuntimes for zero-only width values in cross-reference streams

CVSS 5.1 MediumEPSS 0.0012 · 2nd percentile

Published by the GitHub Advisory Database at 12 Jun 2026, 18:29 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
pypdfPyPI<6.12.06.12.0
Identifiers
GHSA-248m-82v9-q6g6 · CVE-2026-48156 · PYSEC-2026-3004
Weakness (CWE)
CWE-834
Tags
Published
12 Jun 2026
Updated
10 Sept 2026

Machine-written summary

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

pypdf versions before 6.12.0 can take a very long time to parse a crafted PDF whose cross-reference streams have all-zero width fields and large size values. An attacker who supplies such a PDF can cause long runtimes. Upgrade to pypdf 6.12.0 or later.

Written 1 Nov 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
5.1 Medium 4.0 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0012, the 2nd percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 28 May 2026, 16:16 UTC Confirmed by NVD
  2. 31 Oct 2026, 14:11 UTC First seen by agentprime
  3. 31 Oct 2026, 14:11 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.