CVE-2026-22691

Summary

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 Software

Weaknesses

• CWE-1333: CWE-1333: Inefficient Regular Expression Complexity
• CWE-400: CWE-400: Uncontrolled Resource Consumption

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

References

• https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhv
• https://github.com/py-pdf/pypdf/pull/3594
• https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45
• https://github.com/py-pdf/pypdf/releases/tag/6.6.0

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