Bug 2455340 (CVE-2026-5673)

Summary: CVE-2026-5673 libtheora: libtheora: Denial of Service or Information Disclosure via malformed AVI file processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libtheora. This heap-based out-of-bounds read vulnerability exists within the AVI (Audio Video Interleave) parser, specifically in the avi_parse_input_file() function. A local attacker could exploit this by tricking a user into opening a specially crafted AVI file containing a truncated header sub-chunk. This could lead to a denial-of-service (application crash) or potentially leak sensitive information from the heap.
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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: 2455342, 2455343    
Bug Blocks:    

Description OSIDB Bzimport 2026-04-06 09:10:45 UTC 
A heap-based out-of-bounds read flaw was found in libtheora within the avi_parse_input_file() function in avilib.c. The vulnerability occurs when the AVI parser processes a malformed file containing a truncated hdrl sub-chunk. Because the parser lacks sufficient length validation before performing fixed-offset memcpy operations (such as copying the compressor field), it can be triggered to read past the end of the hdrl_data buffer. A local attacker could exploit this by tricking a user into opening a specially crafted AVI file, leading to a denial-of-service (application crash) or potentially leaking information from the heap.