# CVE-2026-110925: OpenSSH shell metacharacter injection in ProxyCommand

Source: https://junglewise.ai/threats/cve-2026-110925-a-flaw-was-found-in-openssh-a-username-entered-on-the-ssh  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-15. Updated: 2026-10-19  
License: CC BY 4.0 with a link back

CVE-2026-110925 · Severity: medium · CVSS 5.4 · Published 2026-10-15

OpenSSH, a widely-used remote access tool, fails to properly sanitize usernames containing shell metacharacters like '$' and backslashes. When a system administrator configures ProxyCommand or Match exec directives, an attacker can inject shell commands by crafting a malicious username, potentially leading to arbitrary command execution on the client side.

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

## Quick answers

**Is CVE-2026-110925 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-110925 being exploited in the wild.

**How severe is CVE-2026-110925?** Medium severity, with a CVSS score of 5.4, published 15 October 2026.

**Which products and versions are affected?** OpenSSH OpenSSH.

**Is there a fix for CVE-2026-110925?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-110925 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-110925?** Check whether you run OpenSSH. 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.

## Technical details

A shell injection vulnerability exists in OpenSSH's handling of the %u token expansion within ProxyCommand and Match exec configuration directives. Usernames containing unescaped '$' characters or non-trailing backslashes are passed directly to the shell without sanitization, allowing an attacker to inject arbitrary shell metacharacters and commands. This requires a vulnerable configuration but can lead to arbitrary code execution in the context of the SSH client.

## Affected products

- OpenSSH OpenSSH

## Timeline

- 2026-10-15: disclosed

## References

- [https://catalog.redhat.com/software/containers/](https://catalog.redhat.com/software/containers/)
- [https://access.redhat.com/downloads/content/package-browser/](https://access.redhat.com/downloads/content/package-browser/)

## Related threats

- [OpenSSH password authentication bypass on musl libc without PAM](https://junglewise.ai/threats/cve-2026-123158-sshd-in-openssh-before-10-6p2-on-linux-when-musl-libc-is-used)
- [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 path traversal in sftp copy](https://junglewise.ai/threats/cve-2026-110923-a-flaw-was-found-in-openssh-during-an-sftp-copy-a-malicious)