GHSL-2026-118: 7-Zip UDF Field OOB Read

Summary

CVECVE-2026-48102
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-05 16:16:41 UTC
Updated2026-06-05 17:04:07 UTC
Description7-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.

Risk And Classification

Primary CVSS: v3.1 3.1 LOW from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Problem Types: CWE-125 | CWE-125 CWE-125: Out-of-bounds Read


VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
3.1CNADECLARED3.1LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mcmilk 7-Zip affected >= 9.11, < 26.01 Not specified

References

ReferenceSourceLinkTags
securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip [email protected] securitylab.github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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