pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/utils.py function readuntil_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82398.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-407"
]
}