CVE-2026-55427
Last modified
CVE-2026-55427 is a high-severity vulnerability rated 8.3/10 on the CVSS scale. 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. EPSS estimates a 0.47% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Coder | Coder | < 2.29.17 |
| Coder | Coder | >= 2.30.0, < 2.32.7 |
| Coder | Coder | >= 2.33.0, < 2.33.8 |
| Coder | Coder | >= 2.34.0, < 2.34.2 |
References
- https://github.com/coder/coder/pull/26154Issue Tracking, Patch
- https://github.com/coder/coder/releases/tag/v2.29.17Release Notes
- https://github.com/coder/coder/releases/tag/v2.32.7Release Notes
- https://github.com/coder/coder/releases/tag/v2.33.8Release Notes
- https://github.com/coder/coder/releases/tag/v2.34.2Release Notes
- https://github.com/coder/coder/security/advisories/GHSA-mcqq-fqgf-rxwmPatch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
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