CVE-2026-40243: CWE-295: Improper Certificate Validation in lxc incus
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.
AI Analysis
Technical Summary
Incus, a system container and VM manager, uses custom TLS verification for OVN database connections that replaces Go's standard server verification. This custom verifier incorrectly builds the trust root set from certificates provided by the peer during handshake rather than anchoring trust to the configured CA certificate. Consequently, in OVN-enabled deployments using these SSL paths, an attacker capable of intercepting or impersonating the OVN endpoint on the management network can present a self-signed certificate that Incus will accept as valid. This breaks the CA-based trust model and permits endpoint impersonation. The vulnerability is identified as CWE-295 (Improper Certificate Validation) and is resolved in Incus version 7.0.0.
Potential Impact
An attacker positioned on the management network who can impersonate or intercept the OVN database endpoint can bypass TLS certificate validation and present a rogue self-signed certificate. This allows the attacker to impersonate the OVN database endpoint, potentially leading to unauthorized access or manipulation of OVN database communications. The CVSS 4.0 score is low (2.3), reflecting the requirement for attacker presence on the management network and high attack complexity.
Mitigation Recommendations
This vulnerability is fixed in Incus version 7.0.0. Users should upgrade to version 7.0.0 or later to resolve this issue. Patch status is not explicitly confirmed beyond the version fix; therefore, verify with the vendor advisory for the latest remediation guidance.
CVE-2026-40243: CWE-295: Improper Certificate Validation in lxc incus
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Incus, a system container and VM manager, uses custom TLS verification for OVN database connections that replaces Go's standard server verification. This custom verifier incorrectly builds the trust root set from certificates provided by the peer during handshake rather than anchoring trust to the configured CA certificate. Consequently, in OVN-enabled deployments using these SSL paths, an attacker capable of intercepting or impersonating the OVN endpoint on the management network can present a self-signed certificate that Incus will accept as valid. This breaks the CA-based trust model and permits endpoint impersonation. The vulnerability is identified as CWE-295 (Improper Certificate Validation) and is resolved in Incus version 7.0.0.
Potential Impact
An attacker positioned on the management network who can impersonate or intercept the OVN database endpoint can bypass TLS certificate validation and present a rogue self-signed certificate. This allows the attacker to impersonate the OVN database endpoint, potentially leading to unauthorized access or manipulation of OVN database communications. The CVSS 4.0 score is low (2.3), reflecting the requirement for attacker presence on the management network and high attack complexity.
Mitigation Recommendations
This vulnerability is fixed in Incus version 7.0.0. Users should upgrade to version 7.0.0 or later to resolve this issue. Patch status is not explicitly confirmed beyond the version fix; therefore, verify with the vendor advisory for the latest remediation guidance.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-10T17:31:45.785Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69fba9cccbff5d86105e9c35
Added to database: 5/6/2026, 8:51:24 PM
Last enriched: 5/6/2026, 9:07:01 PM
Last updated: 5/7/2026, 7:25:48 AM
Views: 10
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.