CVE-2026-55427

Summary

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.

Affected Software

VendorProductVersion RangeStatus
codercoder>= 2.34.0, < 2.34.2affected
codercoder>= 2.33.0, < 2.33.8affected
codercoder>= 2.30.0, < 2.32.7affected
codercoder< 2.29.17affected

Weaknesses

  • CWE-74: CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
  • CWE-78: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

References