CVE-2026-40243: Incus is a system container and virtual machine manager. In versions before 7.0.0, broken TLS validation logic in the OVN database connection logic ca...

Description

Incus is a system container and virtual machine manager. In versions before 7.0.0, broken TLS validation logic in the OVN database connection logic can allow connections to an attacker's OVN database. The OVN client implementations disable Go standard TLS server verification and replace it with custom peer-certificate verification logic. That replacement verifier does not anchor trust in the configured CA certificate. Instead, it constructs the verification root set from certificates supplied by the peer during the handshake, so the configured CA is parsed but not used as the trust anchor for the final verification decision. In OVN-enabled deployments that use these SSL database connection paths, an attacker able to impersonate or intercept the OVN endpoint on the management network can present a rogue self-signed certificate chain, and Incus will accept this certificate as valid. This issue defeats the intended CA-based trust model for OVN database connections and permits endpoint impersonation by an active attacker in a suitable network position. This issue is fixed in version 7.0.0.

Metrics

CVSS 3.1

4.8/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS 4.0

2.3/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.17%

7.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Linuxcontainers	Incus	< 7.0.0

References

https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icnb.goProduct
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icsb.goProduct
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_nb.goProduct
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_sb.goProduct
https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3Exploit, Vendor Advisory
https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3Exploit, Vendor Advisory

Timeline

Published: May 6, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-40243?

Incus is a system container and virtual machine manager. In versions before 7.0.0, broken TLS validation logic in the OVN database connection logic can allow connections to an attacker's OVN database. The OVN client implementations disable Go standard TLS server verification and replace it with custom peer-certificate verification logic. That replacement verifier does not anchor trust in the configured CA certificate. Instead, it constructs the verification root set from certificates supplied by the peer during the handshake, so the configured CA is parsed but not used as the trust anchor for the final verification decision. In OVN-enabled deployments that use these SSL database connection paths, an attacker able to impersonate or intercept the OVN endpoint on the management network can present a rogue self-signed certificate chain, and Incus will accept this certificate as valid. This issue defeats the intended CA-based trust model for OVN database connections and permits endpoint impersonation by an active attacker in a suitable network position. This issue is fixed in version 7.0.0.

How severe is CVE-2026-40243?

CVE-2026-40243 has a CVSS score of 2.3/10 (LOW severity). The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.

How do I fix CVE-2026-40243?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.