pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the children of a TreeObject, for example as part of outlines. This vulnerability is fixed in 6.7.1.
https://github.com/py-pdf/pypdf/security/advisories/GHSA-996q-pr4m-cvgq
https://github.com/py-pdf/pypdf/releases/tag/6.7.1
https://github.com/py-pdf/pypdf/pull/3645
https://github.com/py-pdf/pypdf/commit/bd2f6d052fe5941e85e37082c2a43453d48d1295
Published: 2026-02-20
Updated: 2026-02-20
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium