Incus has an OVN TLS Verification that Accepts Peer-Supplied Roots

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

2.3 · CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-40243: 0.17% estimated exploitation activity in the next 30 days; percentile 6.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Broken TLS validation logic in the OVN database connection logic could allow connections to an attacker's OVN database. OVN uses mTLS for authentication, so the attacker cannot actually perform a full man in the middle attack as they won't be able to authenticated with the real OVN deployment. At best they can provide a replacement empty database which Incus will briefly interact with before hitting errors due to the rest of the OVN stack not reacting to the committed changes. Also worth noting that the OVN control plane is typically run on the same servers that run Incus, there is typically no routing involved between an Incus server and the OVN control plane, making such an attack extremely difficult to pull off in the first place. Details The OVN client implementations within Incus disable Go standard TLS server verification (InsecureSkipVerify: true) and replace it with custom peer-certificate verification logic. That replacement verifier does not anchor trust in the…

Published by the source

4 May 2026, 19:08 UTC

Last modified by the source

8 May 2026, 19:26 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c839-4qxr-j4x3

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# Patch Next advisory brief: CVE-2026-40243

Advisory: Incus has an OVN TLS Verification that Accepts Peer-Supplied Roots
IDs: CVE-2026-40243, GHSA-c839-4qxr-j4x3
Record: https://patchnext.com/advisories/cve-2026-40243 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 2.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/lxc/incus/v6/cmd/incusd 7.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/lxc/incus/v6/cmd/incusd: affected < 7.0.0; fixed in 7.0.0

## Suggested inspection (read-only)
- Go github.com/lxc/incus/v6/cmd/incusd: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/lxc/incus/v6/cmd/incusd.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c839-4qxr-j4x3 (GitHub-reviewed advisory GHSA-c839-4qxr-j4x3 lists affected ranges: Go github.com/lxc/incus/v6/cmd/incusd >=0 <7.0.0)

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