CVE-2026-55427: Coder

High severity, CVSS 8.3. EPSS: 0.5% chance of exploitation in the next 30 days.

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 products

• Coder Coder: before 2.29.17 (fixed in 2.29.17); from 2.30.0, before 2.32.7 (fixed in 2.32.7); from 2.33.0, before 2.33.8 (fixed in 2.33.8); from 2.34.0, before 2.34.2 (fixed in 2.34.2)

Published 2026-07-08. Last modified 2026-07-08.