CVE-2026-40243
Incus OVN TLS verification accepts peer-supplied roots and permits endpoint impersonation
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.
INFO
Published Date :
May 6, 2026, 9:16 p.m.
Last Modified :
Oct. 26, 2026, 7:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Update Incus to version 7.0.0 or later.
- Ensure proper CA certificate configuration for TLS.
- Monitor OVN database connection logs for anomalies.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-40243.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-40243 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-40243
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-40243 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-40243 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 26, 2026
Action Type Old Value New Value Added Translation Title: incus de lxc, Description: Incus es un gestor de contenedores de sistema y máquinas virtuales. En versiones anteriores a la 7.0.0, una lógica de validación TLS defectuosa en la lógica de conexión de la base de datos OVN puede permitir conexiones a la base de datos OVN de un atacante. Las implementaciones del cliente OVN deshabilitan la verificación estándar del servidor TLS de Go y la reemplazan con una lógica de verificación de certificado de par personalizada. Ese verificador de reemplazo no ancla la confianza en el certificado de CA configurado. En su lugar, construye el conjunto raíz de verificación a partir de certificados proporcionados por el par durante el handshake, por lo que la CA configurada se analiza pero no se utiliza como ancla de confianza para la decisión de verificación final. En despliegues habilitados para OVN que utilizan estas rutas de conexión de base de datos SSL, un atacante capaz de suplantar o interceptar el endpoint OVN en la red de gestión puede presentar una cadena de certificados autofirmados maliciosos, e Incus aceptará este certificado como válido. Este problema anula el modelo de confianza basado en CA previsto para las conexiones de la base de datos OVN y permite la suplantación de endpoints por parte de un atacante activo en una posición de red adecuada. Este problema está solucionado en la versión 7.0.0. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'lxc', 'product': 'incus', 'versions': [{'status': 'affected', 'version': '< 7.0.0'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-40243', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-05-07T14:02:44.630167Z'} -
Initial Analysis by [email protected]
May. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:linuxcontainers:incus:*:*:*:*:*:*:*:* versions up to (excluding) 7.0.0 Added Reference Type GitHub, Inc.: https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icnb.go Types: Product Added Reference Type GitHub, Inc.: https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icsb.go Types: Product Added Reference Type GitHub, Inc.: https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_nb.go Types: Product Added Reference Type GitHub, Inc.: https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_sb.go Types: Product Added Reference Type CISA-ADP: https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3 Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 07, 2026
Action Type Old Value New Value Added Reference https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3 -
New CVE Received by [email protected]
May. 06, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:A/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-295 Added Reference https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icnb.go Added Reference https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_icsb.go Added Reference https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_nb.go Added Reference https://github.com/lxc/incus/blob/v6.22.0/internal/server/network/ovn/ovn_sb.go Added Reference https://github.com/lxc/incus/security/advisories/GHSA-c839-4qxr-j4x3