CVE-2026-28351: Pypdf Project Pypdf

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.4, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream using the RunLengthDecode filter. This has been fixed in pypdf 6.7.4. As a workaround, consider applying the changes from PR #3664.

Affected products

• Pypdf Project Pypdf: before 6.7.4 (fixed in 6.7.4)

Published 2026-02-27. Last modified 2026-06-17.