Linux Distros Unpatched Vulnerability : CVE-2026-40243

low Nessus Plugin ID 311660

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- 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. (CVE-2026-40243)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://ubuntu.com/security/CVE-2026-40243

Plugin Details

Severity: Low

ID: 311660

File Name: unpatched_CVE_2026_40243.nasl

Version: 1.9

Type: Local

Agent: unix

Family: Misc.

Published: 5/2/2026

Updated: 5/22/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.3

CVSS v2

Risk Factor: Medium

Base Score: 4.3

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N

CVSS Score Source: CVE-2026-40243

CVSS v3

Risk Factor: Medium

Base Score: 4.8

Temporal Score: 4.6

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Temporal Vector: CVSS:3.0/E:P/RL:U/RC:C

CVSS v4

Risk Factor: Low

Base Score: 2.3

Threat Score: 1.3

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:incus, cpe:/o:canonical:ubuntu_linux:25.10

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Available: true

Exploit Ease: Exploits are available

Reference Information

CVE: CVE-2026-40243