mcmilk 7-Zip up to 26.00 File Identifier Descriptor Parser UdfIn.cpp Open out-of-bounds

Summaryinfo

A vulnerability categorized as problematic has been discovered in mcmilk 7-Zip up to 26.00. The impacted element is the function Open of the file CPP/7zip/Archive/Udf/UdfIn.cpp of the component File Identifier Descriptor Parser. Such manipulation leads to out-of-bounds. This vulnerability is documented as CVE-2026-48102. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in mcmilk 7-Zip up to 26.00. It has been rated as problematic. Affected by this issue is the function Open of the file CPP/7zip/Archive/Udf/UdfIn.cpp of the component File Identifier Descriptor Parser. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality. CVE summarizes:

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.

The advisory is shared for download at securitylab.github.com. This vulnerability is handled as CVE-2026-48102 since 05/20/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

Upgrading to version 26.01 eliminates this vulnerability.

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Productinfo

Type

• File Compression Software

Vendor

• mcmilk

Name

• 7-Zip

Version

• 26

CPE 2.3info

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CPE 2.2info

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