Bug 2449010 (CVE-2026-4426)

Summary: CVE-2026-4426 libarchive: libarchive: Denial of Service via malformed ISO 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, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (`pz_log2_bs`) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2449012, 2449013, 2449011    
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Description OSIDB Bzimport 2026-03-19 12:45:25 UTC 
An Undefined Behavior vulnerability exists in the zisofs decompression logic of the libarchive library. The flaw is caused by improper validation of the pz_log2_bs field, which is directly read from ISO9660 Rock Ridge extensions and used as a shift exponent in arithmetic operations. When a specially crafted ISO file provides an out-of-range value (e.g., ≥64 on 64-bit systems), it triggers undefined behavior due to invalid shift operations, leading to incorrect memory allocation and potential crashes. This vulnerability can be exploited by supplying a malicious ISO file, resulting in denial-of-service conditions in applications that process ISO images.