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

Read our report: OpenBSD OpenSSH flaw allows password authentication bypass →

Affected versions

Product	Affected versions	Fixed in
Openbsd Openssh	before 10.6	10.6
Openbsd Openssh	10.6	–
Openbsd Openssh	10.6	–

Required action (CISA's text)

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.

Description (NVD)

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.

Vendor advisories

• 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

SOURCES

• NVDNVD entry for CVE-2026-123158
• CISA KEVCISA Known Exploited Vulnerabilities catalog
• MICROSOFTmsrc.microsoft.com/update-guide/vulnerability/CVE-2026-1231…
• VENDORmarc.info

Other OpenBSD flaws

• CVE-2020-7247: OpenSMTPD Remote Code Execution Vulnerability

Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.