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

Exploited in the wild High 8.1 EPSS 1.0% 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.

CVE-2026-123158CVE identifier
8.1CVSS 3.1 base score (high)
2026-11-09added to CISA's exploited list (US federal deadline 2026-11-12)
1.0%EPSS: chance of exploitation in the next 30 days (higher than 63% of CVEs)
2026-11-05published

What do these terms mean? CVE · CVSS score · exploited (KEV) · EPSS · backported fix · all terms

What to do now

Check whether you run OpenSSH and which version (commands below).
Install the fixed version for your system: see “Patch it” below.
sudo systemctl restart ssh (Debian/Ubuntu) or sshd (RHEL/SUSE/Fedora/Arch/Amazon); Alpine: rc-service sshd restart; FreeBSD: service sshd restart
Because this flaw is being exploited, also check the server for signs of compromise.

Affected and fixed versions

Affected:

OpenBSD OpenSSH before 10.6p2

Patch it

Use the commands for your system. Distribution packages often keep an older version number with the fix backported, so compare with the fixed package versions in the table below, not only with the upstream version.

Debian

sudo apt update
sudo apt install --only-upgrade openssh-server openssh-client

Ubuntu

sudo apt update
sudo apt install --only-upgrade openssh-server openssh-client

RHEL, AlmaLinux, Rocky, Oracle

sudo dnf upgrade --refresh openssh-server openssh

Fedora

sudo dnf upgrade --refresh openssh-server openssh

SUSE / openSUSE

sudo zypper refresh
sudo zypper update openssh openssh-server

Amazon Linux

sudo dnf upgrade --releasever=latest openssh-server openssh

Arch Linux

sudo pacman -Syu

Alpine

apk update && apk upgrade openssh openssh-server

FreeBSD

pkg update && pkg upgrade openssh-portable (port; the base-system sshd is patched with freebsd-update)

General update steps for every system are on the Linux and Unix & BSD pages; after updating, see which services to restart.

Fix status in Linux distributions

Release	Package	Status	Fixed version / advisory
Debian 12	`openssh`	not fixed yet
Debian 13	`openssh`	not fixed yet
Debian testing	`openssh`	fixed	`1:10.6p2-1`
Debian testing	`openssh-gssapi`	fixed	`1:10.6p2-1`

From the Debian security tracker, Ubuntu CVE tracker and Red Hat Security Data API, refreshed every few hours.

CISA 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

Sources

Page generated automatically from official sources on 2026-11-10 11:23 UTC. Always confirm with your vendor's advisory.