An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires reading a PDF document with long indirect object headers, not terminated by whitespace.
This has been fixed in pypdf==6.18.0.
If you cannot upgrade yet, consider applying the changes from PR #4055.
{
"cwe_ids": [
"CWE-400",
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-01T15:05:53Z",
"nvd_published_at": "2026-09-30T20:17:28Z",
"severity": "HIGH"
}