pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.5, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires accessing a stream which uses the /ASCIIHexDecode filter. This issue has been patched in version 6.7.5.
https://github.com/py-pdf/pypdf/security/advisories/GHSA-9m86-7pmv-2852
https://github.com/py-pdf/pypdf/releases/tag/6.7.5
https://github.com/py-pdf/pypdf/pull/3666
https://github.com/py-pdf/pypdf/commit/648c627d2657447dfb1773412af05a0a5103b98f
Published: 2026-03-06
Updated: 2026-03-06
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
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:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00042