WhatCyber / CISA KEV catalog / CVE-2026-123158
CVE-2026-123158: OpenBSD OpenSSH
OpenBSD OpenSSH Unexpected Status Code or Return Value Vulnerability
Actively exploited (CISA KEV) HIGH severity
Description
OpenBSD OpenSSH on Linux contains an unexpected status code or return value vulnerability that could allow for authentication bypass.
Key facts
- CVSS v3
- 8.1 (HIGH)
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2026-11-05
- Last modified
- 2026-11-10
- NVD status
- Analyzed
- Added to CISA KEV
- 2026-11-09
- CISA due date
- 2026-11-12
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.
This vulnerability affects an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://www.openssh.org/releasenotes.html ; https://alpinelinux.org/posts/2026-11-05-openssh-password-authentication-bypass/ ; https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-123158
Weaknesses (CWE)
- CWE-394
Affected products
- openbsd openssh (versions: 10.6)
- alpinelinux alpine_linux
References
- https://github.com/leonjza/sshhole-lab
- https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482
- https://github.com/predkambrij/sshhole-repro
- https://hachyderm.io/@damienmiller/117563026759098135
- https://marc.info/?l=openssh-unix-dev&m=179388064263131&w=2
- https://news.ycombinator.com/item?id=50377976
- https://news.ycombinator.com/item?id=50378228
- https://www.openssh.org/releasenotes.html#10.6p2
- http://www.openwall.com/lists/oss-security/2026/11/09/27
- https://alpinelinux.org/posts/2026-11-05-openssh-password-authentication-bypass/
- https://github.com/coollabsio/coolify/discussions/12484
- https://github.com/google/goonami-scanner/pull/277
- https://github.com/panubo/docker-sshd/issues/93
- https://news.ycombinator.com/item?id=50379704
- https://isc.sans.edu/diary.html?storyid=33498