CVE-2026-45720

SAML.getSession (internal/pkg/auth/interceptor/saml.go) checks the Used flag on a SAMLAssertion resource and then marks it used in two separate state operations. Because the check and the update are not atomic, concurrent requests carrying the same saml-session token can both observe Used == false, both pass validation, and both return a successful authentication context. An attacker who obtains a valid saml-session token can exploit this window to authenticate as the token's owner multiple times, defeating the one-time-use guarantee.

Severity

• Attack Vector: Local: the attacker needs to either be able to intercept the local, unencrypted traffic or needs access to user's browser.
• Attack Complexity: High: the attacker must first obtain a valid saml-session token belonging to the victim (requires a separate interception step; the token is ephemeral and single-use by design).
• Privileges Required: None: no Omni account is required to carry out the race once the session token is in hand.
• User Interaction: Required: the victim must initiate a SAML authentication flow to produce the session token that the attacker intercepts.
• Scope: Unchanged: the impact stays within Omni's authorization boundary.
• Confidentiality Impact: High: successful exploitation authenticates the attacker as the victim's email identity, granting read access to any resource accessible to that identity.
• Integrity Impact: High: the attacker can confirm one or more public keys under the victim's identity (via ConfirmPublicKey), establishing persistent access credentials tied to the victim's account.
• Availability Impact: High: if the attacker can successfully perform the attack and if the victim is a privileged Omni user, e.g., an Omni Operator or Admin, they can take Omni down.

Credit

This vulnerability was discovered and reported by bugbunny.ai.

• Session replay: A stolen saml-session token can be used more than once, defeating its single-use guarantee.
• Multiple public key confirmations: An attacker who steals the session can confirm N attacker-controlled public keys under the victim's identity in a single stolen session window, creating N persistent long-lived API credentials tied to the victim's account.
• Authentication as victim: Any gRPC endpoint gated by the SAML interceptor can be reached as the victim's email identity during the race window.
• Audit log pollution: Each raced call generates an audit entry attributed to the victim's email, obscuring the attacker's actions.

CVE-2026-45720 has a CVSS score of 7.0 (High). The vector is requires local access, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.6, 1.7.3); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-45720? CVE-2026-45720 is a high-severity security vulnerability in github.com/siderolabs/omni (go), affecting versions < 1.6.6. It is fixed in 1.6.6, 1.7.3.
2. How severe is CVE-2026-45720? CVE-2026-45720 has a CVSS score of 7.0 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/siderolabs/omni are affected by CVE-2026-45720? github.com/siderolabs/omni (go) versions < 1.6.6 is affected.
4. Is there a fix for CVE-2026-45720? Yes. CVE-2026-45720 is fixed in 1.6.6, 1.7.3. Upgrade to this version or later.
5. Is CVE-2026-45720 exploitable, and should I be worried? Whether CVE-2026-45720 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45720 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45720?
   • Upgrade github.com/siderolabs/omni to 1.6.6 or later
   • Upgrade github.com/siderolabs/omni to 1.7.3 or later