OpenSSH Fixes Musl Login Bypass Found With AI Agents
OpenSSH 10.6p2, released Nov. 5, fixes a flaw that let oversized passwords open password-disabled accounts on some musl-based Linux systems.
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WASHINGTON — The OpenSSH project released version 10.6p2 on Nov. 5, 2026, with what it called a critical security workaround for Linux systems that use the musl C library with PAM disabled.
The flaw allowed a password authentication bypass through the sshd server on some of those systems, the OpenSSH release notes said. The project said it considers the root cause to lie outside sshd but fixed it there because sshd is how it can be exploited.
How the bypass works
Accounts can be blocked from password logins by storing an asterisk in place of a password hash, BleepingComputer reported. The musl library’s crypt() function also returns an asterisk when hashing fails, including when a submitted password exceeds 256 bytes, BleepingComputer reported.
An attacker who submits an oversized password can therefore make OpenSSH compare an asterisk with an asterisk and grant a login, according to BleepingComputer. The flaw does not bypass passwords on accounts with valid password hashes, BleepingComputer said.
Researcher Özgün Kültekin, who reported the bug, said it dates to a 2016 OpenSSH change that fixed a username enumeration issue tracked as CVE-2016-6210, BleepingComputer reported. OpenSSH credited Kültekin of Wakefield with the report.
Who is exposed
The flaw affects OpenSSH on musl-based distributions such as Alpine Linux, OpenWrt, Buildroot and Yocto, BleepingComputer reported. Exploitation requires PAM to be disabled, password authentication to be enabled and at least one account with an asterisk password field, according to the report.
Kültekin warned that Alpine Linux’s official AWS and Azure images include a default alpine account with passwordless doas privileges, which could give an attacker root access, BleepingComputer reported. Systems using glibc, such as Debian, Ubuntu and Fedora, are not affected, the report said.
AI in the discovery
Kültekin said the flaw was found using AI agents that ran about 17,600 authentication tests, BleepingComputer reported. The OpenSSH team said in its release notes that it has received a large number of security reports made with AI tools.
The team said several bugs found by AI tools were later found independently by other researchers. It said it would release fixes more often for now because adversaries are likely able to find the same bugs.
What administrators are told to do
Alpine administrators are advised to update with apk upgrade openssh, BleepingComputer reported. Those who cannot update can set PasswordAuthentication no in the SSH server configuration and restart the service, the report said.
What it means
Analysis: The bug sits at the seam between two components, each behaving as designed. Its default exposure in official cloud images makes it relevant to government and contractor systems built on Alpine containers. The OpenSSH notice also signals that AI-assisted bug hunting is shortening the window between discovery and exploitation.
Sources
- OpenSSH: Release notes, OpenSSH 10.6p2
- BleepingComputer: OpenSSH flaw lets attackers log into password-disabled Linux accounts
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