Medium severity · published May 6, 2026
CVE-2026-40243
Incus OVN TLS verification accepts peer-supplied roots and permits endpoint impersonation
4.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
IN
incus · lxc
< 7.0.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-40243
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-40243
Product
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icnb.go
Product
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icsb.go
Product
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_nb.go
Product
https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_sb.go
Exploit
https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3
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