Omni: TOCTOU race condition allows multiple concurrent uses of a single-use SAML session token
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.
- Published
- Sep 17, 2026
- Updated
- Sep 24, 2026
- EPSS
- 0.1% · 3th percentile
- CWE
- CWE-294
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Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.1%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.0
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
siderolabs omni
- < 1.6.6, >= 1.7.0, < 1.7.3affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Go | github.com/siderolabs/omni | from 1.7.0 · before 1.7.3 | 1.7.3 |
| Go | github.com/siderolabs/omni | before 1.6.6 | 1.6.6 |
Same product
siderolabs: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-45726Omni: Reader-level users can retrieve imported cluster CA keys via ResourceService30Monitor
- CVE-2025-61688Omni leaks information via the API30Monitor
- CVE-2025-59836Omni is Vulnerable to DoS via Empty Create/Update Resource Requests30Monitor
- CVE-2026-45723Omni: Operator can traverse image-factory API paths via unsanitized `talos_version` in CreateSchematic10Monitor
- CVE-2025-59824Omni Wireguard SideroLink potential escape2Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Go:github.com/siderolabs/omni | 1.6.6 | Package registry (OSV) |
| Go:github.com/siderolabs/omni | 1.7.3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-294 · Authentication Bypass by Capture-replayCVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Session SidejackingCAPEC-102likelihood: High · High
- KerberoastingCAPEC-509High
- Remote Services with Stolen CredentialsCAPEC-555Very High
- Windows Admin Shares with Stolen CredentialsCAPEC-561
- Reusing Session IDs (aka Session Replay)CAPEC-60likelihood: High · High
- Use of Captured Hashes (Pass The Hash)CAPEC-644likelihood: Medium · High
- Use of Captured Tickets (Pass The Ticket)CAPEC-645likelihood: Low · High
- Use of Known Kerberos CredentialsCAPEC-652likelihood: Medium · High
ATT&CK techniques
- Remote ServicesT1021
- Remote Services:SMB/Windows Admin SharesT1021.002
- Email Collection:Remote Email CollectionT1114.002
- External Remote ServicesT1133
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Use Alternate Authentication Material:Pass The HashT1550.002
- Use Alternate Authentication Material:Pass The TicketT1550.003
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Adversary-in-the-MiddleT1557
- Steal or Forge Kerberos TicketsT1558
- Steal or Forge Kerberos Tickets:KerberoastingT1558.003
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/siderolabs/omni/commit/272d3f4dd00e778b39fde09afde35575fe13ef13
- github.com/siderolabs/omni/commit/4c4c1e2d8226914f26774a309a91595f168ee921
- github.com/siderolabs/omni/commit/ced79da6c032d2103803eb53343d0916cc957d2a
- github.com/siderolabs/omni/pull/2816
- github.com/siderolabs/omni/releases/tag/v1.6.6
- github.com/siderolabs/omni/releases/tag/v1.7.3
- github.com/siderolabs/omni/security/advisories/GHSA-5x9f-6vg5-qg4m
Vendor advisories and official records. Exploit/PoC links are deliberately left out.