CVE-2026-40260: pypdf: Manipulated XMP metadata entity declarations can exhaust RAM

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-04-17 · updated 2026-06-17
Weakness: CWE-776

Description

pypdf is a free and open-source pure-python PDF library. In versions prior to 6.10.0, manipulated XMP metadata entity declarations can exhaust RAM. An attacker who exploits this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the XMP metadata. This issue has been fixed in version 6.10.0.

Affected products

py-pdf pypdf: before 6.10.0 — fixed in 6.10.0

How to fix

Upgrade to a fixed version: py-pdf pypdf 6.10.0. Check the vendor advisory for mitigations.

References

https://github.com/py-pdf/pypdf/commit/b15a374e5ca648d4878e57c3b2c0551e7f8cc7f8
https://github.com/py-pdf/pypdf/pull/3724
https://github.com/py-pdf/pypdf/releases/tag/6.10.0
https://github.com/py-pdf/pypdf/security/advisories/GHSA-3crg-w4f6-42mx

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