pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive time and memory when an application accesses the page count of a crafted encrypted PDF whose page tree declares a forged /Count value. Even after successful decryption, page-count retrieval trusts the unvalidated declared count instead of walking the page tree, allowing the attacker-controlled value to drive excessive work and memory use. This issue is fixed in version 6.21.3.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 7.1 · py-pdfNVD modified 2026-10-29 20:41
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 4
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-62m5-6wh8-28x7 x_refsource_confirm
- https://github.com/py-pdf/pypdf/pull/4270 x_refsource_misc
- https://github.com/py-pdf/pypdf/commit/82b91951dc74496bb3efe6465434f041bb6a5e6b x_refsource_misc
- https://github.com/py-pdf/pypdf/releases/tag/6.21.3 x_refsource_misc