CVE-2026-55427: Coder SSH configuration injection in coder config-ssh

CVE-2026-55427 · Severity: high · CVSS 8.3 · Published 2026-07-08

Coder is a platform used by organizations to manage and deploy remote development environments. A security vulnerability in the Coder command-line tool could allow a compromised or malicious server to inject unauthorized settings into a developer's local SSH configuration file. If exploited, this could allow an attacker to intercept connections, redirect traffic, or gain unauthorized access to the developer's machine or other sensitive systems.

Technologies: Coder, github.com/coder/coder (Go), github.com/coder/coder/v2 (Go). Vendors: Coder, Go.

Quick answers

Is CVE-2026-55427 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55427 being exploited in the wild.
How severe is CVE-2026-55427?
High severity, with a CVSS score of 8.3, published 8 July 2026.
Which products and versions are affected?
Coder < 2.29.17, >= 2.30.0 < 2.32.7, >= 2.33.0 < 2.33.8, >= 2.34.0 < 2.34.2; github.com/coder/coder (Go) SEMVER:introduced=0; github.com/coder/coder/v2 (Go) SEMVER:introduced=0,fixed=2.29.17,introduced=2.30.0,fixed=2.32.7,introduced=2.33.0,fixed=2.33.8,introduced=2.34.0,fixed=2.34.2, SEMVER:introduced=2.34.0,fixed=2.34.2.
Is there a fix for CVE-2026-55427?
Yes. github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55427 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-55427?
Check whether you run Coder, github.com/coder/coder (Go) or github.com/coder/coder/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later
    go get github.com/coder/coder/v2@v2.34.2

Technical details

A configuration injection vulnerability exists in the Coder CLI's 'coder config-ssh' command. The tool writes server-supplied SSH settings, specifically 'HostnameSuffix' and 'SSHConfigOptions', directly into the user's local '~/.ssh/config' file without sanitizing newlines or restricting directives. An attacker who controls a Coder deployment, performs a man-in-the-middle attack, or has administrative access to these settings can inject arbitrary SSH directives. This can lead to unauthorized command execution or credential exfiltration via SSH configuration features. The issue is resolved in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 by implementing strict character validation that rejects newlines and control characters.

Affected products

  • Coder Coder < 2.29.17, >= 2.30.0 < 2.32.7, >= 2.33.0 < 2.33.8, >= 2.34.0 < 2.34.2

Identifiers

  • CVE-2026-55427
  • GHSA-mcqq-fqgf-rxwm
  • GO-2026-5913

Timeline

  • 2026-06-09: other: Fix pull request submitted
  • 2026-06-11: patched: Security releases published for 2.32.x, 2.33.x, and 2.34.x
  • 2026-06-12: patched: Security release published for 2.29.x
  • 2026-07-08: disclosed: CVE published to NVD

References

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