# CVE-2026-125370: Kubero 3.0.0 through 3.1.1 Authentication Bypass via Hardcoded JWT Secret

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

Kubero 3.0.0 through 3.1.1 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to forge administrative JWTs by using a hardcoded fallback signing secret when JWT_SECRET is unset. Attackers can sign tokens with arbitrary role, userGroups and permissions claims, which JwtStrategy.validate() trusts without a database lookup, to take control of pipelines, applications, users and API tokens.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- kubero-dev / kubero: ≥ 3.0.0; ≤ 3.1.1 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 9.3 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 9.8 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-321

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/kubero-dev/kubero/issues/786 (CNA: VulnCheck; issue-tracking)

- https://github.com/kubero-dev/kubero (CNA: VulnCheck; product)

- https://github.com/kubero-dev/kubero/blob/bcb52376b19347b8c36bc445ddf3e4bff4a5c168/server/src/auth/strategies/jwt.strategy.ts#L13-L32 (CNA: VulnCheck; technical-description)

- https://www.vulncheck.com/advisories/kubero-3.0.0-through-3.1.1-authentication-bypass-via-hardcoded-jwt-secret (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-125370; retrieved 2026-11-10; source updated 2026-11-09

Revision: 014353fb02df38b17393abecab67584c9527d3264a672c1b52e4b81abc75d5c3

Canonical: https://y2.dev/cve/CVE-2026-125370

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.