An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks.
This has been fixed in pypdf 6.6.2.
If projects cannot upgrade yet, consider applying the changes from PR #3610.
{
"severity": "MODERATE",
"github_reviewed": true,
"cwe_ids": [
"CWE-835"
],
"github_reviewed_at": "2026-01-26T23:37:57Z",
"nvd_published_at": "2026-01-27T20:16:24Z"
}