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.
History

Fri, 20 Feb 2026 21:30:00 +0000

Type Values Removed Values Added
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.
Title pypdf possibly has long runtimes for malformed FlateDecode streams
Weaknesses CWE-770
References
Metrics cvssV4_0

{'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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-20T21:12:33.537Z

Reserved: 2026-02-17T03:08:23.491Z

Link: CVE-2026-27026

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-20T22:16:29.023

Modified: 2026-02-20T22:16:29.023

Link: CVE-2026-27026

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.