CVE-2026-48156

pypdf: Possible long runtimes for zero-only width values in cross-reference streams

State: Published
Severity: 5.1 Medium
Published: May 28, 2026
Updated: May 30, 2026
Reserved: May 20, 2026

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

Scores

CVSS	Score	Vector	Source
4.0	5.1 Medium	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-834 Excessive Iteration

Affected Products

Product	Versions
pypdfpy-pdf	< 6.12.0Affected

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-248m-82v9-q6g6
https://github.com/py-pdf/pypdf/pull/3791
https://github.com/py-pdf/pypdf/releases/tag/6.12.0

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.