pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime. This quadratic runtime blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. This issue has been addressed in PR 808 and versions from 1.27.9 include this fix. Users are advised to upgrade. There are no known workarounds for this vulnerability.
CVE-2023-36810
CVSS base score
6.2 (v3.1)
Severity
MEDIUM
Attack vector
Local
Weakness
CWE-407
Last modified
November 2, 2026
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
py-pdf pypdf
References
- github.com Exploit, Issue Tracking, Vendor Advisory
- github.com Patch
- github.com Exploit, Patch, Vendor Advisory
- lists.debian.org
- github.com Exploit, Issue Tracking, Vendor Advisory
- github.com Patch
- github.com Exploit, Patch, Vendor Advisory
- lists.debian.org