CVE-2026-40243
Undergoing Analysis Undergoing Analysis - In Progress
BaseFortify

Publication date: 2026-05-06

Last updated on: 2026-05-06

Assigner: GitHub, Inc.

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.
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Meta Information
Published
2026-05-06
Last Modified
2026-05-06
Generated
2026-05-07
AI Q&A
2026-05-07
EPSS Evaluated
N/A
NVD
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-295 The product does not validate, or incorrectly validates, a certificate.
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in Incus versions before 7.0.0, specifically in the TLS validation logic used for connecting to the OVN database. The OVN client disables the standard Go TLS server verification and replaces it with custom peer-certificate verification. However, this custom verifier does not properly anchor trust in the configured Certificate Authority (CA) certificate. Instead, it builds the trust root from certificates provided by the peer during the handshake, ignoring the configured CA as the trust anchor.

As a result, an attacker who can impersonate or intercept the OVN endpoint on the management network can present a rogue self-signed certificate chain. Incus will accept this certificate as valid, allowing the attacker to impersonate the OVN database endpoint. This defeats the intended CA-based trust model and enables endpoint impersonation by an active attacker.

This issue is fixed in Incus version 7.0.0.


How can this vulnerability impact me? :

This vulnerability can allow an attacker positioned on the management network to impersonate the OVN database endpoint by presenting a rogue certificate. This can lead to unauthorized access to the OVN database connection, potentially allowing the attacker to intercept, manipulate, or disrupt communications between Incus and the OVN database.

Such unauthorized access could compromise the integrity and confidentiality of the data exchanged, potentially affecting the security of system containers and virtual machines managed by Incus.


What immediate steps should I take to mitigate this vulnerability?

The vulnerability is fixed in Incus version 7.0.0. Immediate mitigation involves upgrading Incus to version 7.0.0 or later.

Since the issue involves broken TLS validation logic in OVN database connections, ensure that your OVN endpoints are not exposed to untrusted networks and restrict access on the management network to trusted entities only.


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