CVE-2026-24688: pypdf has possible Infinite Loop when processing outlines/bookmarks
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks.
Patches
This has been fixed in pypdf 6.6.2.
Workarounds
If projects cannot upgrade yet, consider applying the changes from PR #3610.
Other sources
pypdf is a free and open-source pure-python PDF library. An attacker who uses an infinite loop vulnerability that is present in versions prior to 6.6.2 can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. This has been fixed in pypdf 6.6.2. If projects cannot upgrade yet, consider applying the changes from PR #3610 manually.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-24688?
CVE-2026-24688 is classified with a severity that indicates a potential denial of service due to an infinite loop when processing PDF outlines or bookmarks.
How do I fix CVE-2026-24688?
To fix CVE-2026-24688, upgrade to pypdf version 6.6.2 or later.
What software is affected by CVE-2026-24688?
CVE-2026-24688 affects pypdf versions prior to 6.6.2.
Can CVE-2026-24688 be exploited remotely?
Yes, an attacker can exploit CVE-2026-24688 remotely by crafting a malicious PDF with specific outlines/bookmarks.
What should I do if I cannot upgrade pypdf to fix CVE-2026-24688?
If upgrading is not possible, consider implementing input validation or sandboxing to mitigate the effects of CVE-2026-24688.