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PYSEC-2026-4160
pypdf: Possible large memory usage when retrieving alphabetical page labels
Quick fix
PYSEC-2026-4160 — pypdf: upgrade to the fixed version with the command below.
pip install --upgrade 'pypdf>=6.19.0'Details
### Impact
An attacker who uses this vulnerability can craft a PDF which leads to large memory consumption. This requires accessing the page labels of a document with large alphabetical labels.
### Patches
This has been fixed in [pypdf==6.19.0](https://github.com/py-pdf/pypdf/releases/tag/6.19.0).
### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#4096](https://github.com/py-pdf/pypdf/pull/4096).
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-w23x-9jrw-r45c[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-103000[ADVISORY]
- https://github.com/py-pdf/pypdf/pull/4096[WEB]
- https://github.com/py-pdf/pypdf/commit/0d8b5a8832cde1ba308b5c27567b879b7b7eed4a[WEB]
- https://github.com/py-pdf/pypdf[PACKAGE]
- https://github.com/py-pdf/pypdf/releases/tag/6.19.0[WEB]
- https://pypi.org/project/pypdf[PACKAGE]
- https://github.com/advisories/GHSA-w23x-9jrw-r45c[ADVISORY]