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🛡️ CVE-2026-48104 on Ubuntu — 7zip

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2026-48104 as tracked by Ubuntu, for the package 7zip. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: None.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

UBUNTU-CVE-2026-48104 is classified as CWE-125: Out-of-bounds Read. The code reads past the limits of a buffer, exposing adjacent memory contents or crashing the process.

Affected software

UBUNTU-CVE-2026-48104 is recorded against 2 packages.

  • 7zip
  • p7zip

Timeline and source

Published on 5 June 2026 and last revised on 12 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
securitylab.github.com (Report)

Other advisories for this package

7zip has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-125: Out-of-bounds Read) in other software:

CVE-2026-48104 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-05
Updated 2026-08-20
Modified 2026-06-12
Fix URL N/A

Affected Packages

Software From version Fixed in
7zip — —
p7zip — —

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