CVE-2026-71852: pypdf: Possible long runtimes/large memory usage for large CID font width ranges

Severity: low (CVSS 3.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-07 · updated 2026-10-24
Weakness: CWE-834

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause long runtimes and large memory consumption when pypdf/_font.py function Font._collect_cid_character_widths expands unusually large CID font /W width ranges or excessive width entries during text extraction. This issue is fixed in 6.15.0.

Affected products

py-pdf pypdf: before 6.15.0 — fixed in 6.15.0

How to fix

Upgrade to a fixed version: py-pdf pypdf 6.15.0. Check the vendor advisory for mitigations.

References

https://github.com/py-pdf/pypdf/commit/51cb6acf9e8a35b77e90b4d87d28fe3e1416d7d7
https://github.com/py-pdf/pypdf/pull/3946
https://github.com/py-pdf/pypdf/releases/tag/6.15.0
https://github.com/py-pdf/pypdf/security/advisories/GHSA-fwg2-594c-jp42

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