CVE-2026-22691
mediumpypdf is a free and open-source pure-python PDF library.
Vendor / product: Py-pdf — pypdf
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
5.3
5.3 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-01-10 05:16
Modified: 2026-11-02 16:06
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-11-03 07:34 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
py-pdf / pypdf <6.6.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Patch / mitigation: https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45
Patch / mitigation: https://github.com/py-pdf/pypdf/pull/3594
Patch / mitigation: https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhv
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
Data sources
NVD CVE API 2.0 — fetched 2026-11-03 07:34 UTC · record ↗