pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.2 can craft a PDF which leads to the RAM being exhausted. This requires accessing an image using `/FlateDecode` with large size values. This has been fixed in pypdf 6.10.2. As a workaround, one may apply the changes from the patch manually.
https://github.com/py-pdf/pypdf/security/advisories/GHSA-x284-j5p8-9c5p
https://github.com/py-pdf/pypdf/releases/tag/6.10.2
https://github.com/py-pdf/pypdf/pull/3734
https://github.com/py-pdf/pypdf/commit/ac734dab4eef92bcce50d503949b4d9887d89f11
Published: 2026-04-22
Updated: 2026-04-22
Base Score: 6.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/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: 4.8
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium