CVE-2026-55427: Github.com/coder/coder/v2 Coder Vulnerable To SSH Config Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mcqq-fqgf-rxwm",
  "modified" : "2026-07-06T20:53:54Z",
  "published" : "2026-07-06T20:53:54Z",
  "aliases" : [ "CVE-2026-55427" ],
  "summary" : "Coder vulnerable to SSH config injection via unsanitized server-supplied values in `coder config-ssh`",
  "details" : "### Summary\n\n`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.\n\n> **Note:** 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.\n\n### Impact\n\nA server administrator or an attacker who controlled the server, could inject a directive such as `ProxyCommand` and achieve arbitrary code execution on any developer workstation that ran `coder config-ssh`. Injected commands ran with the local user's privileges and applied to all SSH connections, not just Coder workspaces.\n\n### Patches\n\nThe fix validates `HostnameSuffix` and `SSHConfigOptions` against a strict character set that rejects newlines and other control characters.\n\nThe fix was backported to all supported release lines:\n\n| Release line | Patched version |\n|---|---|\n| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |\n| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |\n| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |\n| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |\n\n### Workarounds\n\nInspect `coder config-ssh --dry-run` output before applying changes.\n\n### Resources\n\n- Fix: #26154\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22437) for independently disclosing this issue!",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.34.0"
      }, {
        "fixed" : "2.34.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.33.0"
      }, {
        "fixed" : "2.33.8"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.30.0"
      }, {
        "fixed" : "2.32.7"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/coder/coder/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.29.17"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/coder/coder/security/advisories/GHSA-mcqq-fqgf-rxwm"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/coder/coder/pull/26154"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/coder/coder"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-74", "CWE-78" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-06T20:53:54Z",
    "nvd_published_at" : null
  }
}