CVE-2026-48102: 7-zip Out-of-bounds Read

Vulnerability summary

CVE-2026-48102 is a medium (CVSS 4.3) Out-of-bounds Read vulnerability in 7-zip. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.2% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 05-06-2026
   PublishedVulnerability first disclosed.
2. 09-06-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.