An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing arrays and/or dictionaries with lots of elements.
This has been fixed in pypdf==6.21.0.
If you cannot upgrade yet, consider applying the changes from PR #4218.
{
"cwe_ids": [
"CWE-400"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-22T16:49:40Z",
"nvd_published_at": "2026-10-21T16:17:26Z",
"severity": "MODERATE"
}