MEDIUMCVSS 6.9EPSS 0.3%

CVE-2026-59937

pypdf: Possible long runtimes for repeated malformed cross-reference entries

Published: 2026-07-23
Modified: 2026-07-23
EPSS percentile: 27%
Aliases: GHSA-55h5-xmcq-c37v
Sources: github-advisory

Summary

### Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with repeated malformed cross-reference streams. ### Patches This has been fixed in [pypdf==6.14.0](https://github.com/py-pdf/pypdf/releases/tag/6.14.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3887](https://github.com/py-pdf/pypdf/pull/3887).

Affected packages

Ecosystem	Package	Affected versions	Fixed versions
PyPI	pypdf	—	6.14.0

Remediation: Upgrade to 6.14.0 or later.

References

https://github.com/advisories/GHSA-55h5-xmcq-c37v

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

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EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.