← Back to CVEs

CVE-2026-22691

MEDIUM

5.3

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.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/10/2026

Last Modified1/22/2026

Sourcenvd

Honeypot Sightings0

Affected Products

pypdf_project:pypdf

Weaknesses (CWE)

CWE-400CWE-1333

References

https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45(security-advisories@github.com)

https://github.com/py-pdf/pypdf/pull/3594(security-advisories@github.com)

https://github.com/py-pdf/pypdf/releases/tag/6.6.0(security-advisories@github.com)

https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhv(security-advisories@github.com)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.