CVE-2026-22691
pypdf has possible long runtimes for malformed startxref
5.3
MEDIUM
CVSS 3.1
EPSS 0.02%
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.
How to fix CVE-2026-22691
To remediate CVE-2026-22691, upgrade the affected package to a fixed version below.
- —no fix listed
- —no fix listed
- —upgrade to 6.6.0 or later
Is CVE-2026-22691 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0
- from 0
- from 0, < 6.6.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U |
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |