# CVE-2026-125331: HarnessRouter: Service-only routes that write an organization's provider connections could be reached through a multi-tenant console with a made-up bearer

Status: published. Published: 2026-11-10. Updated: 2026-11-12.

HarnessRouter is a self-hosted unified API for running agent harnesses with sessions, streaming, files, cancellation, and failure handling. Prior to 0.31.8, a console that is not in self-hosted mode attaches the server's internal key to requests carrying an Authorization header before validating the bearer, while the service-only PUT and GET /v1/orgs/{org}/connections/{name}, PUT /v1/orgs/{org}/policy/{backend}, and /internal/* routes trust that key and take the organization from the URL. In a multi-organization deployment, a remote caller can use a made-up bearer to rewrite another organization's provider connection to an attacker-controlled endpoint, causing later prompts to be disclosed and attacker-controlled responses to influence tasks. This issue is fixed in version 0.31.8.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- HarnessRouter / harnessrouter: < 0.31.8 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 9.1 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N; source: CNA: GitHub_M

- CVSS 3.1: 9.1 (critical); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.30% as of 2026-11-12; percentile 22.62%

- SSVC: exploitation none; automatable yes; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-862, CWE-863

## Exploit evidence

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

## References

- https://github.com/HarnessRouter/harnessrouter/security/advisories/GHSA-p6cq-54cg-8mpv (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/HarnessRouter/harnessrouter/pull/418 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/HarnessRouter/harnessrouter/commit/28609ec65ed671112d7e5418926bbd3cb3b25c00 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/HarnessRouter/harnessrouter/releases/tag/v0.31.8 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/HarnessRouter/harnessrouter/commit/28609ec65ed671112d7e5418926bbd3cb3b25c00 (security-advisories@github.com)

- https://github.com/HarnessRouter/harnessrouter/pull/418 (security-advisories@github.com)

- https://github.com/HarnessRouter/harnessrouter/releases/tag/v0.31.8 (security-advisories@github.com)

- https://github.com/HarnessRouter/harnessrouter/security/advisories/GHSA-p6cq-54cg-8mpv (security-advisories@github.com)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-125331; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125331; retrieved 2026-11-11; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-125331; retrieved 2026-11-12; source updated Not reported

Revision: 242fcc01f8ced5f337f41f024838f9cce1b247e64327ce2c6d745039e8ae26dd

Canonical: https://y2.dev/cve/CVE-2026-125331

## 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.