MajorExploited now Active exploitation

CVE-2026-123158: OpenBSD OpenSSH Unexpected Status Code or Return Value Vulnerability

CISA KEV · officialPublished Nov 9, 2026Risk 77/100

OpenBSD OpenSSH on Linux contains an unexpected status code or return value vulnerability that could allow for authentication bypass. Vendor: OpenBSD — OpenSSH Required Action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Due: 2026-11-12

Recommended action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA remediation due: 2026-11-12

Technical details

Vendor: OpenBSD
Product: OpenSSH
Exploitation: active
Evidence: official

Evidence and sources

This record is attributed to CISA KEV. Exploitation status and remediation guidance are kept separate from the vulnerability's technical severity.

Open primary source