CVE-2026-55427

Description

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `coder config-ssh` wrote server-supplied SSH settings (`HostnameSuffix`, `SSHConfigOptions`) into the user's `~/.ssh/config` without sanitizing embedded newlines or restricting directives so a malicious or compromised Coder server could inject arbitrary SSH configuration. Practical exploitation requires control of the server-supplied values through a malicious or compromised deployment, a man-in-the-middle position or admin access to the `HostnameSuffix` and `SSHConfigOptions` settings. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates `HostnameSuffix` and `SSHConfigOptions` against a strict character set that rejects newlines and other control characters. As a workaround, inspect `coder config-ssh --dry-run` output before applying changes.

CVSS Vector

Affected Products

References

• https://github.com/coder/coder/pull/26154
• https://github.com/coder/coder/releases/tag/v2.29.17
• https://github.com/coder/coder/releases/tag/v2.32.7
• https://github.com/coder/coder/releases/tag/v2.33.8
• https://github.com/coder/coder/releases/tag/v2.34.2
• https://github.com/coder/coder/security/advisories/GHSA-mcqq-fqgf-rxwm