CVE-2026-27026

medium

Description

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 long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h

https://github.com/py-pdf/pypdf/releases/tag/6.7.1

https://github.com/py-pdf/pypdf/pull/3644

https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016

Details

Source: Mitre, NVD

Published: 2026-02-20

Updated: 2026-02-20

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

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