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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| py-pdf | pypdf | < 6.6.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pypdf | 6.9.0-1 | — |
| Debian 13 | pypdf | No fix yet | — |
| Debian 12 | pypdf +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pypdf | No fix yet | — |
| Ubuntu 26.04 LTS | pypdf | No fix yet | — |
| Ubuntu 25.10 | pypdf | No fix yet | — |
| Ubuntu 24.04 LTS | pypdf +1 | No fix yet | — |
| Ubuntu 22.04 LTS | pypdf2 | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | pypdf2 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | pypdf2 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | pypdf2 | No fix yet | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | pypdf | < 6.6.0 | 6.6.0 | GHSA-4f6g-68pf-7vhv |
Advisories 1
- WID-SEC-2026-1730 Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 16, 2026