pypdf: Possible long runtimes for repeated references to the same missing object

Summary

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.2, an attacker can craft a PDF that repeatedly references the same nonexistent indirect object, causing relevant file parts such as pages to trigger repeated full-file recovery loads and long runtimes when accessed. This issue is fixed in version 6.21.2.

Remediation

1. Inventory every py-pdf pypdf deployment, including staging.
2. No fixed version appears in the public sources yet. Check the references below and the vendor directly.

References

• Referencehttps://github.com/py-pdf/pypdf/commit/68a0e5046cc9e14a6c24a21a713f3c7fbde18b4b
• Referencehttps://github.com/py-pdf/pypdf/pull/4240
• Referencehttps://github.com/py-pdf/pypdf/releases/tag/6.21.2
• Referencehttps://github.com/py-pdf/pypdf/security/advisories/GHSA-6c7f-9265-g8fw