Bug 2467522 (CVE-2026-40243)

Summary: CVE-2026-40243 github.com/lxc/incus: incus: Incus: Authentication bypass due to broken OVN TLS validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Incus, a system container and virtual machine manager. The Open Virtual Network (OVN) database connection logic contains broken Transport Layer Security (TLS) validation. A remote attacker, by impersonating or intercepting the OVN endpoint on the management network, can present a rogue self-signed certificate. This allows Incus to accept the invalid certificate as legitimate, thereby bypassing the intended certificate authority (CA)-based trust model and enabling endpoint impersonation.
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Bug Depends On: 2477848    
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Description OSIDB Bzimport 2026-05-06 21:03:20 UTC 
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.