An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires removing an object from a tree, for example an outline item.
This has been fixed in pypdf==6.20.1.
If you cannot upgrade yet, consider applying the changes from PR #4188.
{
"cwe_ids": [
"CWE-835"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-21T16:55:10Z",
"nvd_published_at": null,
"severity": "MODERATE"
}