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PYSEC-2026-3656
pypdf: Possible long runtimes/large memory usage for large CID font width ranges
Quick fix
PYSEC-2026-3656 — pypdf: upgrade to the fixed version with the command below.
pip install --upgrade 'pypdf>=6.15.0'Details
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the font width entries of a font with unusually large values, for example during text extraction.
### Patches
This has been fixed in [pypdf==6.15.0](https://github.com/py-pdf/pypdf/releases/tag/6.15.0).
### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#3946](https://github.com/py-pdf/pypdf/pull/3946).
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-fwg2-594c-jp42[WEB]
- https://github.com/py-pdf/pypdf/pull/3946[WEB]
- https://github.com/py-pdf/pypdf/commit/51cb6acf9e8a35b77e90b4d87d28fe3e1416d7d7[WEB]
- https://github.com/py-pdf/pypdf[PACKAGE]
- https://github.com/py-pdf/pypdf/releases/tag/6.15.0[WEB]
- https://pypi.org/project/pypdf[PACKAGE]
- https://github.com/advisories/GHSA-fwg2-594c-jp42[ADVISORY]
- https://nvd.nist.gov/vuln/detail/CVE-2026-71852[ADVISORY]