Bug 2528466

Summary: CVE-2026-82398 python-pypdf: pypdf: Denial of Service via inefficient handling of non-whitespace inputs [fedora-all]
Product: [Fedora] Fedora Reporter: Marian Rehak <mrehak>
Component: python-pypdfAssignee: Davide Cavalca <davide>
Status: CLOSED RAWHIDE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: davide, tadej.j
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["479e3084-6808-4f21-8d1d-2f526f8946ef"]}
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Last Closed: 2026-09-11 10:09:09 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2526567    

Description Marian Rehak 2026-09-04 10:44:34 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.
Comment 1 Tadej Janež 2026-09-11 10:09:09 UTC 
Version 6.16.2 is in rawhide.

For Fedora 44/43, I'm reluctant to upgrade them since it would be upgrading 2 major versions (from 4.2.0 to 6.16.2) in a stable release.