PYSEC-2026-3011 pypdf: Manipulated FlateDecode predictor parameters can exhaust RAM

Impact An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using /FlateDecode with a /Predictor unequal 1 and large predictor parameters. Patches This has been fixed in pypdf==6.10.2. Workarounds If you cannot...

PYSEC-2026-3026 pypdf: Manipulated FlateDecode image dimensions can exhaust RAM

Impact An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing an image using /FlateDecode with large size values. Patches This has been fixed in pypdf==6.10.2. Workarounds If you cannot upgrade yet, consider applying the changes fro...

PT-2026-59636

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires accessing a stream which uses the /ASCIIHexDecode filter. Patches This has been fixed in pypdf==6.7.5. Workarounds If you cannot upgrade yet, consider applying the changes from PR 3666...

PT-2026-59639

Impact 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. Patches This has been fixed in pypdf==6.7.4. Workarounds If you cannot upgrade yet, consider applying the changes from PR 36...

PT-2026-59643

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with wrong large /Size values or object streams with wrong large /N values. Patches This has been fixed in pypdf==6.10.1. Workarounds If you cannot upgrade yet,...

pypdf has possible long runtimes for malformed startxref

ImpactAn attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected...

CVE-2026-27888

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.3, an attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing the xfa property of a reader or writer and the corresponding stream being compressed using /FlateDecode...

PT-2026-4845

Name of the Vulnerable Software and Affected Versions pypdf versions prior to 6.6.2 Description A flaw exists in the pypdf library that allows attackers to trigger an infinite loop by creating a PDF file with cyclic outline references. This requires accessing the outlines or bookmarks within the...