FKIE_CVE-2026-55438

Vulnerability from fkie_nvd - Published: 2026-07-08 01:16 - Updated: 2026-07-08 19:38
Severity
5.8 (Medium) - CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
6.8 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N
Summary
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.
References
security-advisories@github.comhttps://github.com/coder/coder/pull/26085Issue Tracking, Patch
security-advisories@github.comhttps://github.com/coder/coder/pull/26086Issue Tracking, Patch
security-advisories@github.comhttps://github.com/coder/coder/releases/tag/v2.29.17Release Notes
security-advisories@github.comhttps://github.com/coder/coder/releases/tag/v2.32.7Release Notes
security-advisories@github.comhttps://github.com/coder/coder/releases/tag/v2.33.8Release Notes
security-advisories@github.comhttps://github.com/coder/coder/releases/tag/v2.34.2Release Notes
security-advisories@github.comhttps://github.com/coder/coder/security/advisories/GHSA-5wg6-jmq2-53pwPatch, Vendor Advisory
Impacted products
Vendor Product Version
coder coder *
coder coder *
coder coder *
coder coder *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*",
              "matchCriteriaId": "F97FAF48-192E-4814-82A5-085C44F1D261",
              "versionEndExcluding": "2.29.17",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*",
              "matchCriteriaId": "7ABD4A9B-6AE8-47D8-A1B7-91E42EE0481B",
              "versionEndExcluding": "2.32.7",
              "versionStartIncluding": "2.30.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*",
              "matchCriteriaId": "F759EEF3-6EAE-475B-85F8-38E7D7B47438",
              "versionEndExcluding": "2.33.8",
              "versionStartIncluding": "2.33.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:coder:coder:*:*:*:*:*:go:*:*",
              "matchCriteriaId": "397A02BF-6CF6-40B1-B792-D7CB9D229050",
              "versionEndExcluding": "2.34.2",
              "versionStartIncluding": "2.34.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder\u0027s subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL\u0027s username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker\u0027s crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace\u0027s actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available."
    }
  ],
  "id": "CVE-2026-55438",
  "lastModified": "2026-07-08T19:38:38.473",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.3,
        "impactScore": 4.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.3,
        "impactScore": 4.0,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55438",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-08T16:56:25.900709Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-08T01:16:28.150",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Issue Tracking",
        "Patch"
      ],
      "url": "https://github.com/coder/coder/pull/26085"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Issue Tracking",
        "Patch"
      ],
      "url": "https://github.com/coder/coder/pull/26086"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/coder/coder/releases/tag/v2.29.17"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/coder/coder/releases/tag/v2.32.7"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/coder/coder/releases/tag/v2.33.8"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Release Notes"
      ],
      "url": "https://github.com/coder/coder/releases/tag/v2.34.2"
    },
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Patch",
        "Vendor Advisory"
      ],
      "url": "https://github.com/coder/coder/security/advisories/GHSA-5wg6-jmq2-53pw"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-346"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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