CVE-2026-55427
Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`
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 Breakdown
AV:NAttack VectorAC:HAttack ComplexityPR:NPrivileges RequiredUI:RUser InteractionS:CScopeC:HConfidentialityI:HIntegrityA:HAvailabilityWeaknesses
Affected Products
Exploitability
Attack Graph
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MITRE ATT&CK
2 techniquesReferences
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