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Fencer Vulns
high 8.8

CVE-2026-33898 json

Local Incus UI web server vulnerable to nuthentication bypass

published 2026-03-26 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-16490 , GHSA-453r-g2pg-cxxq , GO-2026-4879

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

Incus is a system container and virtual machine manager. Prior to version 6.23.0, the web server spawned by `incus webui` incorrectly validates the authentication token such that an invalid value will be accepted. `incus webui` runs a local web server on a random localhost port. For authentication, it provides the user with a URL containing an authentication token. When accessed with that token, Incus creates a cookie persisting that token without needing to include it in subsequent HTTP requests. While the Incus client correctly validates the value of the cookie, it does not correctly validate the token when passed int the URL. This allows for an attacker able to locate and talk to the temporary web server on localhost to have as much access to Incus as the user who ran `incus webui`. This can lead to privilege escalation by another local user or an access to the user's Incus instances and possibly system resources by a remote attack able to trick the local user into interacting with the Incus UI web server. Version 6.23.0 patches the issue.

Patch / fix

  • go github.com/lxc/incus/v6/cmd/incus 6.23.0
  • go github.com/lxc/incus/v6 6.23.0
  • linuxcontainers incus 6.23.0
  • incus Debian 14 7.0.0-1

debian advisories DEBIAN-CVE-2026-33898

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • incus openSUSE Tumbleweed 6.23-1.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:10450-1

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-2026-33898 updated cvss 8.2

incus: Incus: Privilege escalation and unauthorized access due to improper authentication token validation in web UI

  • 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
7 mo ago

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/lxc/incus/v6/cmd/incus
<6.23.0
6.23.0
go github.com/lxc/incus
all versions
 no fix listed
go github.com/lxc/incus/v6
<6.23.0
6.23.0

Affected products

  • lxc incus

Classification

Weakness

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.