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PYSEC-2026-3610

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

Quick fix

PYSEC-2026-3610 — pypdf: upgrade to the fixed version with the command below.

pip install --upgrade 'pypdf>=6.14.0'

Details

### 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).

Are you affected?

Enter the version of the package you're using.

Affected packages

PyPI/pypdf

Introduced in: 0Fixed in: 6.14.0

Fixpip install --upgrade 'pypdf>=6.14.0'

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v[WEB]
https://nvd.nist.gov/vuln/detail/CVE-2026-59937[ADVISORY]
https://github.com/py-pdf/pypdf/pull/3887[WEB]
https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae[WEB]
https://github.com/py-pdf/pypdf[PACKAGE]
https://github.com/py-pdf/pypdf/releases/tag/6.14.0[WEB]
https://pypi.org/project/pypdf[PACKAGE]
https://github.com/advisories/GHSA-55h5-xmcq-c37v[ADVISORY]