An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires loading an invalid dictionary.
This has been fixed in pypdf==6.21.3.
If you cannot upgrade yet, consider applying the changes from PR #4265.
{
"cwe_ids": [
"CWE-400",
"CWE-405"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-30T23:08:39Z",
"nvd_published_at": "2026-10-29T21:17:19Z",
"severity": "HIGH"
}