pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.
https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v
https://github.com/py-pdf/pypdf/releases/tag/6.14.0
https://github.com/py-pdf/pypdf/pull/3887
https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae
Published: 2026-07-08
Updated: 2026-07-08
Base Score: 5.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:P
Severity: Medium
Base Score: 7.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium