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Vulnerability record · CVE-2026-123158 · published 5 November 2026

CVE-2026-123158: Openbsd openssh vulnerability

Openbsd · Openssh

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.

8.1 CVSS 3.1 High CISA KEV since 9 Nov 2026 EPSS 19% · top 2.7% CWE-394 · CWE-394
8.1CVSS 3.1 base score
19%EPSS exploitation probability, 30 days
YesIn CISA KEV, fix deadline passed
1Affected product versions listed by NVD
18References, 2 tagged exploit
10 Nov 2026Last modified by NVD

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.

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

Exploitation in the wild

CISA added CVE-2026-123158 to the Known Exploited Vulnerabilities catalog on 9 November 2026 as "OpenBSD OpenSSH Unexpected Status Code or Return Value Vulnerability". 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. Federal deadline 12 November 2026.

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/leonjza/sshhole-lab ExploitThird Party Advisory
https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482 Patch
https://github.com/predkambrij/sshhole-repro ExploitThird Party Advisory
https://hachyderm.io/@damienmiller/117563026759098135 Third Party Advisory
https://marc.info/?l=openssh-unix-dev&m=179388064263131&w=2 Mailing ListVendor Advisory
https://news.ycombinator.com/item?id=50377976 Issue Tracking
https://news.ycombinator.com/item?id=50378228 Issue Tracking
https://www.openssh.org/releasenotes.html#10.6p2 Release Notes
http://www.openwall.com/lists/oss-security/2026/11/09/27 Mailing List
https://alpinelinux.org/posts/2026-11-05-openssh-password-authentication-bypass/ Third Party Advisory
https://github.com/coollabsio/coolify/discussions/12484 Third Party Advisory
https://github.com/google/goonami-scanner/pull/277 Third Party Advisory
https://github.com/panubo/docker-sshd/issues/93 Third Party Advisory
https://news.ycombinator.com/item?id=50379704 Issue Tracking
https://isc.sans.edu/diary.html?storyid=33498 Not Applicable
https://sshhole.com Third Party Advisory
https://sshole.events.greynoise.io/ Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-123158 US Government Resource

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-123158), CISA KEV, FIRST EPSS (scores of 2026-11-11). This page is refreshed as NVD updates the record.