CVE-2026-57204: Pypdf Project Pypdf

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

Affected products

• Pypdf Project Pypdf: before 6.13.3 (fixed in 6.13.3)

Published 2026-06-30. Last modified 2026-07-06.