7-Zip is a file archiver with a high compression ratio. Versions 9.18 through 26.00 contain an uninitialized heap read in the SquashFS archive handler caused by a sparsely populated index array. In the SquashFS handler, _blockToNode is allocated with capacity for every metadata block but populated only when an inode crosses a block boundary, so a crafted image with few inodes spanning many blocks leaves most slots holding raw heap contents (the underlying allocator does not zero-initialize POD storage). When OpenDir looks up an attacker-influenced blockIndex (derived from the RootInode superblock field), it reads two of these uninitialized slots and passes them as the left/right bounds of a binary search over _nodesPos, which dereferences the midpoint without bounds checking; if the resulting value happens to match the search key, the returned index is used to read a full node struct from _nodes whose fields feed further directory parsing, forming a chained OOB read primitive that is heap-layout-dependent and not reliably triggerable. The SquashFS handler is enabled by default in stock 7z.dll and the issue triggers during Open() with no interaction beyond opening the file; impact is denial of service from wild-pointer dereference and potential heap information disclosure, with no write primitive. Version 26.01 fixes the issue.
References
| Link | Resource |
|---|---|
| https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/ | Exploit Patch Third Party Advisory |
| https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/ | Exploit Patch Third Party Advisory |
Configurations
History
No history.
Information
Published : 2026-06-05 17:16
Updated : 2026-06-17 10:54
NVD link : CVE-2026-48104
Mitre link : CVE-2026-48104
CVE.ORG link : CVE-2026-48104
JSON object : View
Products Affected
7-zip
- 7-zip