pypdf has inefficient decoding of array-based streams

GHSA-qpxp-75px-xjcp · CVE-2026-33123

Published Mar 18, 2026 · Modified Mar 23, 2026

Description

Impact

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and/or large memory usage. This requires accessing an array-based stream with lots of entries.

Patches

This has been fixed in pypdf==6.9.1.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #3686.

References

WEB https://github.com/py-pdf/pypdf/security/advisories/GHSA-qpxp-75px-xjcp
ADVISORY https://nvd.nist.gov/vuln/detail/CVE-2026-33123
WEB https://github.com/py-pdf/pypdf/pull/3686
PACKAGE https://github.com/py-pdf/pypdf
WEB https://github.com/py-pdf/pypdf/releases/tag/6.9.1

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