Is there a public exploit for CVE-2026-125331?

No public exploit for CVE-2026-125331 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-125331?

CVE-2026-125331 scores CVSS 9.1 (v3.1), rated critical. EPSS puts the chance of exploitation in the next 30 days at 0.3%.

What does CVE-2026-125331 affect?

CVE-2026-125331 affects HarnessRouter HarnessRouter.

9.1 Critical

HarnessRouter is a self-hosted unified API for running agent harnesses with sessions, streaming, files, cancellation, and failure handling.

CVE-2026-125331

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.

Assessment

CVSS: 9.1 (v3.1)
Severity: Critical
EPSS: 0.3% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 10 November 2026
Last updated: 12 November 2026
Affected: HarnessRouter · HarnessRouter
Assigner: GitHub_M

CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

At the source

EUVD (ENISA)

References

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