# CVE-2026-123158: OpenSSH password authentication bypass on musl libc without PAM

Source: https://junglewise.ai/threats/cve-2026-123158-sshd-in-openssh-before-10-6p2-on-linux-when-musl-libc-is-used  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-05  
License: CC BY 4.0 with a link back

CVE-2026-123158 · Severity: critical · CVSS 8.1 · Exploited in the wild · Published 2026-11-05

OpenSSH is the widely-deployed remote access service that allows secure shell login to servers. On Alpine Linux and other systems using musl libc without PAM, attackers can bypass password authentication by submitting passwords between 256 and 1024 characters, gaining unauthorized server access without valid credentials.

Technologies: [OpenBSD Openssh](https://junglewise.ai/threats/technologies/openssh), [OpenSSH](https://junglewise.ai/threats/technologies/openssh-openssh). Vendors: [OpenBSD](https://junglewise.ai/threats/vendors/openbsd), [OpenSSH](https://junglewise.ai/threats/vendors/openssh).

## Quick answers

**Is CVE-2026-123158 exploited in the wild?** Yes. CVE-2026-123158 is known to be exploited in the wild, first recorded on 9 November 2026. Treat it as urgent.

**How severe is CVE-2026-123158?** Critical severity, with a CVSS score of 8.1, published 5 November 2026.

**Which products and versions are affected?** OpenSSH before 10.6p2 on Linux with musl libc without PAM.

**Is there a fix for CVE-2026-123158?** Yes: fixed in 10.6p2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123158 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-2026-123158?** Check whether you run OpenBSD Openssh or OpenSSH at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 10.6p2

## Technical details

The vulnerability is a password authentication bypass in sshd when musl libc is used without PAM, caused by misinterpretation of password hash format that permits certain long passwords to be accepted for specific account configurations. This affects OpenSSH versions before 10.6p2 on Linux; the attack requires network access to sshd with password authentication enabled and can succeed against accounts with certain configurations without user interaction. The OpenSSH project has applied a workaround in the auth-passwd.c code path to reject this bypass.

## Affected products

- OpenSSH OpenSSH before 10.6p2 on Linux with musl libc without PAM

## Timeline

- 2026-11-05: disclosed

## References

- [https://github.com/leonjza/sshhole-lab](https://github.com/leonjza/sshhole-lab)
- [https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482](https://github.com/openssh/openssh-portable/commit/4353fdc43ef646c43a8dda7025cc1a898caf1482)

## Related threats

- [OpenSSH decompression memory exhaustion](https://junglewise.ai/threats/cve-2026-110927-a-flaw-was-found-in-openssh-after-compression-is-negotiated-a)
- [OpenSSH GSSAPI credential persistence authentication bypass](https://junglewise.ai/threats/cve-2026-110924-a-flaw-was-found-in-openssh-with-gssapi-authentication-enabled-a)
- [OpenSSH compression dictionary information disclosure](https://junglewise.ai/threats/cve-2026-110926-a-flaw-was-found-in-openssh-when-compression-is-negotiated)
- [OpenSSH shell metacharacter injection in ProxyCommand](https://junglewise.ai/threats/cve-2026-110925-a-flaw-was-found-in-openssh-a-username-entered-on-the-ssh)
- [OpenSSH path traversal in sftp copy](https://junglewise.ai/threats/cve-2026-110923-a-flaw-was-found-in-openssh-during-an-sftp-copy-a-malicious)