CVE-2026-113794: pypdf: Possible infinite loop when hitting EOF in standard xref table

Severity: medium (CVSS 6.0 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-21 · updated 2026-10-28
Weakness: CWE-835

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.20.0, an attacker can craft an incomplete PDF that ends inside a standard cross-reference table, causing pypdf to mishandle the unexpected end of file and enter an infinite loop. This issue is fixed in version 6.20.0.

Affected products

py-pdf pypdf: before 6.20.0

References

https://github.com/py-pdf/pypdf/commit/37e1cd681744bac38b159f7e1c614eee8d639c58
https://github.com/py-pdf/pypdf/issues/4169
https://github.com/py-pdf/pypdf/pull/4170
https://github.com/py-pdf/pypdf/releases/tag/6.20.0
https://github.com/py-pdf/pypdf/security/advisories/GHSA-39mj-jf6j-2qj3

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