Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Pypdf Project | Pypdf | < 6.6.0 |
Related Weaknesses (CWE)
References
- https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45Patch
- https://github.com/py-pdf/pypdf/pull/3594Issue TrackingPatch
- https://github.com/py-pdf/pypdf/releases/tag/6.6.0Release Notes
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhvVendor AdvisoryMitigation
FAQ
What is CVE-2026-22691?
CVE-2026-22691 is a vulnerability with a CVSS score of 5.3 (MEDIUM). pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which...
How severe is CVE-2026-22691?
CVE-2026-22691 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-22691?
Check the references section above for vendor advisories and patch information. Affected products include: Pypdf Project Pypdf.