GHSL-2026-122 7-Zip Ar SYMDEF OOB Read
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.
Summary
7-Zip is a file archiver with a high compression ratio. Versions 9.18 through 26.00 contain a heap out-of-bounds read in 7-Zip Ar handler BSD SYMDEF parser. A 4-byte heap out-of-bounds read exists in the Unix ar archive parser in 7-Zip. When parsing a BSD-style __.SYMDEF symbol table, the ParseLibSymbols function reads a 32-bit namesSize field via Get32 at a position that can equal the buffer size, reading 4 bytes past the end of the heap allocation. This reads uninitialized heap data under the default allocator. Version 26.01 patches the issue.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA 7-Zip (mcmilk) Fixed in 26.01
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-48112
References
More mcmilk vulnerabilities
- TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
- TI-2026-35535 GHSL-2026-140_7-Zip: 7-Zip has a heap buffer overflow via NTFS compressed stream buffer under-allocation CVSS 3.1HIGH 8.8
- TI-2026-35532 7-Zip SquashFS Fragment Offset Overflow (GHSL-2026-116) CVSS 3.1HIGH 8.1
- TI-2026-35551 GHSL-2026-121 7-Zip UEFI DEPEX OOB Read CVSS 3.1HIGH 7.1
- TI-2026-35543 GHSL-2026-119 7-Zip WIM SecurityId OOB read CVSS 3.1HIGH 7.1
- TI-2026-35544 GHSL-2026-120: 7-Zip SquashFS BlockToNode uninitialized heap read CVSS 3.1MEDIUM 4.2
Sources
- CVE-2026-48112 · CVE Program
- CVE-2026-48112 · NVD
- FIRST EPSS
- CVE-2026-48112 · Red Hat security data · CC BY 4.0
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