CVE-2026-45720 Omni: TOCTOU race condition allows multiple concurrent uses of a single-use SAML session token
Attackers can exploit a race condition to reuse single-use SAML tokens, gaining unauthorized access and creating persistent credentials as the victim.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-45720?
CVE-2026-45720 is a high-severity vulnerability in siderolabs omni, published on 17 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
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.
Which versions are affected by CVE-2026-45720?
5 open source packages ship an affected version, including github.com/siderolabs/omni.
| Package | Affected | Fixed in |
|---|---|---|
github.com/siderolabs/omni Go | All versions | 1.6.6, 1.7.3 |
github.com/siderolabs/omni Go | All versions | 1.6.6 |
github.com/siderolabs/omni Go | All versions | 1.6.6 |
github.com/siderolabs/omni Go | From 1.7.0 | 1.7.3 |
github.com/siderolabs/omni Go | From 1.7.0 | 1.7.3 |
How do I fix CVE-2026-45720?
Upgrade github.com/siderolabs/omni to a fixed version for your release line: 1.6.6 or 1.7.3.
Is CVE-2026-45720 being exploited?
There is no known exploitation of CVE-2026-45720 in the wild and no public exploit code.
Sources
Also known as GHSA-5x9f-6vg5-qg4m, GO-2026-5160.