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VulnerabilityPublished Updated

CVE-2026-33898: lxc incus · Improper Authentication

Affects lxc incusSource CVE Database V5

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Not known to be exploited · CVSS 8.8 High : upgrade to 6.23.0 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.23.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade incus and lxc/incus to 6.23.0.

Affected software

ProductAffectedFixed in
lxcincusAffected
  • <6.23.0
Fixed in
  • 6.23.0
GitHublxc/incuspkg:github/lxc/incusOther threatsAffected
  • <6.23.0
Fixed in
  • 6.23.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Version 6.23.0 of Incus includes an official fix for this vulnerability. Users should upgrade to version 6.23.0 or later to remediate this issue. Until upgraded, restrict access to the local web server spawned by `incus webui` to trusted users only and avoid interacting with untrusted URLs that may contain authentication tokens.

Description

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.

References

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