Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`

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.

Timeline

1. Jul 7, 2026, 11:55 PM UTCCVE published
2. Jul 8, 2026, 1:09 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Jul 8, 2026, 1:10 PM UTCRecord last updated

Affected versions

• coder coder

  From 2.34.0 · fixed in 2.34.2; From 2.33.0 · fixed in 2.33.8; From 2.30.0 · fixed in 2.32.7; fixed in 2.29.17

• github.com/coder/coderGo

  All versions

• github.com/coder/coder/v2Go

  fixed in 2.29.17; From 2.30.0 · fixed in 2.32.7; From 2.33.0 · fixed in 2.33.8; From 2.34.0 · fixed in 2.34.2

• github.com/coder/coder/v2Go

  From 2.34.0 · fixed in 2.34.2

• github.com/coder/coder/v2Go

  From 2.33.0 · fixed in 2.33.8

• github.com/coder/coder/v2Go

  From 2.30.0 · fixed in 2.32.7

• github.com/coder/coder/v2Go

  fixed in 2.29.17

References 6