Vulnerability · NVD

CVE-2026-48104

CVE-2026-48104, medium severity (CVSS 4.2): 1 tracked app concerned, all fixed or indeterminable on their current version.

Severity (CVSS): 4.2
Exploitation: 0.2 %
Tracked apps: 1
Still exposed: 0

Published on 2026-06-05

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.

Attack vector : Network No privileges required

Show raw CVSS vector

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

EPSS 0.25% exploit very unlikely percentile 14.1%

Tracked apps referencing this CVE

For each app: the affected range, the fixing version, and where the tracked app stands today.

7-Zip Windows winget:7zip.7zip

Affected ≥9.18 <26.01 Fixed in 26.01 Latest tracked 26.03 patched

Observed affected builds (19)

26.00 25.01 25.00 24.09 24.08 24.07 24.06 24.05 23.01 22.01 22.00 21.07 21.06 19.00 19.00.00.0 18.06 18.05 18.01 16.04

Vulnerable CPE configurations (1)

Vendor	Product	Platform	Versions	CPE 2.3 URI
7-zip	7-zip All platforms (wildcard)	All platforms (wildcard)	≥9.18 <26.01	cpe:2.3:a:7-zip:7-zip::::::::

View on NVD ↗ Advisory · securitylab.github.com

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