CVE-2026-123158: OpenBSD OpenSSH Unexpected Status Code or Return Value Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 4 days after the CVE record was published.
VulnCheck KEV lists it since , 3 days before CISA. It cites 7 public reports, the first from .
- How likely is exploitation in the next 30 days?
- 18.9%
EPSS score, percentile 97.3 of all scored records
- How severe?
- 8.1 High
CVSS v3.1 base score, given by the CNA
- What should I do?
No patch or vendor advisory is listed in the CVE record. Check OpenBSD's advisories.
CISA (deadline ): Apply mitigations in accordance with vendor instructions … Full text
- Which versions are affected?
Affected
- before 10.6p2
Source: CISA KEV 2026.11.10, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
Description
sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass (related to misinterpretation of whether a string is intended to be a password hash). For some configurations of accounts, any password between 256 and 1024 characters succeeds. An example of a platform using musl libc without PAM is Alpine Linux.
Source: CVE List, as of . About the data.
What to do
Advisories and patches
No patch, vendor advisory or mitigation is listed in the CVE record. Check OpenBSD's own security advisories for a fix, and compare your version with the affected versions below.
Required action, set by CISA
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 due date for this action: .
Linked from CISA's catalog entry
- 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
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- 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
This summary is based on the CVE record and CISA's catalog entry as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
Versions by product, as listed in the CVE record (1 product)
| Status | Versions |
|---|---|
| Affected | before 10.6p2 |
Versions not listed are: unaffected.
Source: CVE List, as of . About the data.
Weakness
CWE-394
- CWE-394: Unexpected Status Code or Return Value
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CVE record last updated | |
| CISA due date for the required action |
References
8
More exploited OpenBSD vulnerabilities
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