CVE-2026-40243Public exploit

Endpoint impersonation via peer-supplied TLS roots

Published May 6, 2026 · Updated May 6, 2026

Improper certificate validation in Linux Containers Incus before 7.0.0 allows attackers to impersonate OVN database endpoints. The four OVN client constructors disable standard server verification, then build the final trust pool from certificates supplied by the peer instead of the configured CA. Reachability requires an OVN-enabled SSL database path and control-plane network position; OVN mTLS prevents access to the real deployment, limiting interaction to a replacement database before errors occur.

CVSS severity2.3
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Linux Containers Incus before 7.0.0 allows attackers to impersonate OVN database endpoints. The four OVN client constructors disable standard server verification, then build the final trust pool from certificates supplied by the peer instead of the configured CA. Reachability requires an OVN-enabled SSL database path and control-plane network position; OVN mTLS prevents access to the real deployment, limiting interaction to a replacement database before errors occur.

The record

CVE
CVE-2026-40243
Published
May 6, 2026
Updated
May 6, 2026
Vendor
Linux Containers
Product
Incus
Classifications
CWE-295, T1557
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.0.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Linux Containers · Incusversion=< 7.0.0

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
2.3GitHub Security AdvisoryCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
2.3GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-295Improper Certificate Validation
T1557Adversary-in-the-Middle

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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