pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF can provide unusually large alphabetical page-label values that cause pypdf/_page_labels.py to generate strings beyond a reasonable page-label length when an application retrieves document page labels, consuming excessive memory and potentially making the application unavailable. This issue is fixed in version 6.19.0.
https://github.com/py-pdf/pypdf/security/advisories/GHSA-w23x-9jrw-r45c
https://github.com/py-pdf/pypdf/releases/tag/6.19.0
https://github.com/py-pdf/pypdf/pull/4096
https://github.com/py-pdf/pypdf/commit/0d8b5a8832cde1ba308b5c27567b879b7b7eed4a
Published: 2026-09-30
Updated: 2026-10-01
Named Vulnerability: GHSA-w23x-9jrw-r45c
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 5.5
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 8.7
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00524