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Vulnerability · Published Sep 17, 2026 · Assigned by GitHub_M

CVE-2026-45720Omni: TOCTOU race condition allows multiple concurrent uses of a single-use SAML session token

High 7.0

In plain English

A high-severity security flaw in omni from siderolabs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.0High
Exploit odds (30 days)0.1%top 96.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Omni manages Kubernetes on bare metal, virtual machines, or in a cloud. Prior to 1.6.6 and from 1.7.0 until 1.7.3, SAML.getSession in internal/pkg/auth/interceptor/saml.go checks SAMLAssertion.Used and marks it used in separate state operations. Concurrent requests carrying the same captured saml-session token can each observe the assertion as unused and obtain authentication as the victim before either update is visible. The attacker can invoke SAML-protected gRPC endpoints, use ConfirmPublicKey to create multiple persistent credentials tied to the victim, and generate audit entries attributed to the victim, with the resulting access potentially affecting confidentiality, integrity, and availability according to the victim's privileges. This issue is fixed in versions 1.6.6 and 1.7.3.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/siderolabs/omni1.6.6GHSA-5x9f-6vg5-qg4m
Gogithub.com/siderolabs/omni1.7.3GHSA-5x9f-6vg5-qg4m
Gogithub.com/siderolabs/omni1.6.6, 1.7.3GO-2026-5160

Affected products (as reported)

VendorProductVersions
siderolabs omni < 1.6.6>= 1.7.0, < 1.7.3

Weakness: CWE-294, CWE-367 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

References