Summary
pypdf: Possible large memory usage when retrieving alphabetical page labels
Advisory 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.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #4096.
References
- https://github.com/advisories/GHSA-w23x-9jrw-r45c
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-w23x-9jrw-r45c
- https://nvd.nist.gov/vuln/detail/CVE-2026-103000
- https://github.com/py-pdf/pypdf/pull/4096
- https://github.com/py-pdf/pypdf/commit/0d8b5a8832cde1ba308b5c27567b879b7b7eed4a
- https://github.com/py-pdf/pypdf/releases/tag/6.19.0
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