CVE-2026-22691
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 6.9.0-1 |
| forky | Fixed | 6.9.0-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| PyPI | pypdf | <6.6.0 | 6.6.0 |
References
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhv
- https://nvd.nist.gov/vuln/detail/CVE-2026-22691
- https://github.com/py-pdf/pypdf/pull/3594
- https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45
- https://github.com/py-pdf/pypdf
- https://github.com/py-pdf/pypdf/releases/tag/6.6.0
- https://security-tracker.debian.org/tracker/CVE-2026-22691
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.