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[ CVE-2026-119205 · Published 29 Oct 2026 ]

pypdf has possible infinite loop when cloning dictionaries

CVSS 5.5 EPSS <1%Fix available

[ Description ]Official description

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop when cloning or duplicating a crafted cyclic DictionaryObject. Clone traversal checked generated destination references rather than the original source references, allowing some source cycles to evade the visited-object check. This issue is fixed in version 6.21.4.

[ Fixes ]Fixes and patches

  • pypdf 6.21.4Fixed version · GitHub Advisories · pip package pypdf: upgrade to 6.21.4 or later (affected < 6.21.4)
  • Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
  • Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
  • Patch on github.comVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD

[ Packages ]Affected open-source packages

[ References ]References