Bug 2485485 (CVE-2026-48102)

Summary: CVE-2026-48102 7-Zip: 7-Zip: Information disclosure and denial of service via crafted UDF image
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in 7-Zip. A remote attacker could exploit a heap out-of-bounds read vulnerability in the UDF (Universal Disk Format) disc image handler by tricking a user into opening a specially crafted UDF image file. This could lead to limited information disclosure, where an attacker might gain small pieces of sensitive data, or a denial of service (DoS), causing the application to crash. There is no evidence of arbitrary code execution.
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Bug Depends On: 2485489, 2485491    
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Description OSIDB Bzimport 2026-06-05 16:01:27 UTC 
7-Zip is a file archiver with a high compression ratio. Versions 9.11 through 26.00 contain a heap out-of-bounds read of up to 3 bytes in the UDF disc image handler's File Identifier Descriptor parser. In CFileId::Parse (CPP/7zip/Archive/Udf/UdfIn.cpp), after validating size < 38 + idLen + impLen and advancing processed to 38 + impLen + idLen, the alignment-padding loop reads p[processed] while incrementing up to 3 times to reach a 4-byte boundary, and the processed <= size bounds check only runs after the loop. When (38 + impLen + idLen) % 4 != 0 and 38 + impLen + idLen == size, the loop reads 1 to 3 bytes past the end of the exact-size heap buffer allocated via buf.Alloc((size_t)item.Size). The UDF handler is registered for .iso and .udf files and auto-detected by signature, and the OOB read triggers during Open() when listing or extracting a crafted UDF image. Impact is limited to information disclosure (a 1-bit oracle per OOB byte via open/fail behavior) and denial of service (crash under hardened allocators); there is no write primitive. Version 26.01 fixes the issue.