pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/22xxx/CVE-2026-22691.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-1333",
"CWE-400"
]
}{
"source": [
"CPE_RANGE",
"REFERENCES"
],
"cpe": "cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "6.6.0"
}
]
}