An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires opening a file with large/wrong upper limits in the xref table.
This has been fixed in pypdf==6.21.2.
If you cannot upgrade yet, consider applying the changes from PR #4239.
{
"cwe_ids": [
"CWE-834"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-23T20:54:12Z",
"nvd_published_at": null,
"severity": "HIGH"
}