CVE & CISA-KEV Catalog

CVE-2026-40243

MEDIUM
4.8
CVSS v3
NVD

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.

How to fix

Remediation Available
incusDebian
Fixed in:6.0.4-2+deb13u7CVE-2026-40243
Fixed in:7.0.0-1CVE-2026-40243

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityLow
IntegrityLow
AvailabilityNone

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

Exploit Intelligence

0.17%probability of exploitation in 30 days
7thpercentile

Low risk: more likely to be exploited than 7% of all known CVEs.

References

Related Vulnerabilities

Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2015-4000Low3.7100%-Fix
CVE-2020-0601High8.189%KEVFix
CVE-2009-3555Critical9.887%-Fix
CVE-2022-26923High8.883%KEVFix
CVE-2023-27823Critical9.853%--
CVE-2022-42979High8.824%--
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Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-08.