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Fencer Vulns
high 7.8

CVE-2026-8933 json

snap-confine Local Privilege Escalation via Capabilities Misconfiguration or Flaw in Execution Environment Setup

published 2026-07-21 3 mo ago modified 2026-07-22 3 mo ago also EUVD-2026-46262

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A local privilege escalation vulnerability exists in snap-confine, a set-capabilities core component used internally by Canonical snapd to construct the secure execution environment for snap applications. This vulnerability uniquely affects versions of snap-confine configured with set-capabilities (rather than standard set-uid-root installations). Due to a flaw in how privilege boundaries or security sandboxes are initialized when the binary runs under limited ambient capabilities, a local, unprivileged attacker can exploit this behavior to bypass intended restrictions and execute arbitrary code. Successful exploitation allows the local user to elevate their privileges to full root authority.

Patch / fix

  • Canonical Ubuntu 26.04 LTS 2.76+ubuntu26.04.3
  • Canonical Ubuntu 24.04 LTS 2.76+ubuntu24.04.1
  • Canonical Ubuntu 22.04 LTS 2.76+ubuntu22.04.1
  • snapd Debian 14 2.76.3-1

debian advisories DEBIAN-CVE-2026-8933

  • snapd Ubuntu 22.04 LTS 2.76+ubuntu22.04.1
  • snapd Ubuntu 24.04 LTS 2.76+ubuntu24.04.1
  • snapd Ubuntu 26.04 LTS 2.76+ubuntu26.04.3

ubuntu advisories UBUNTU-CVE-2026-8933

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-8933 updated cvss 7.8

snap-confine: snapd: snap-confine: Local Privilege Escalation via Insecure Privilege Boundary Initialization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Canonical Ubuntu 26.04 LTS
  • Canonical Ubuntu 24.04 LTS
  • Canonical Ubuntu 22.04 LTS

Classification

Weakness
  • CWE-250 Execution with Unnecessary Privileges

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.