CVE-2026-84310

Impact

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires accessing the outlines of a document with either lots of entries or nested outlines with long re-used nesting paths.

Patches

This has been fixed in pypdf==6.16.1.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #3966.