GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

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

Vulnerability from cvelistv5 – Published: 2026-07-08 00:10 – Updated: 2026-07-08 13:57
VLAI
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 · CISA-ADP (v2.0.3)
Decision recorded 2026-07-08 13:56 UTC
CWE
  • CWE-522 - Insufficiently Protected Credentials
  • CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
Assigner
References
Impacted products
Vendor Product Version CPE status
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
guessed Create a notification for this product.
Show details on NVD website
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",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-55431",
      "date": "2026-09-20",
      "epss": "0.00336",
      "percentile": "0.27112"
    },
    "nvd": {
      "cve": {
        "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 2.29.7, 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."
          }
        ],
        "id": "CVE-2026-55431",
        "lastModified": "2026-07-08T19:42:45.880",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "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"
              },
              "exploitabilityScore": 1.3,
              "impactScore": 5.8,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 6.1,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "LOW",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "CHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.8,
              "impactScore": 2.7,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-55431",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-08T13:56:53.370657Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-07-08T01:16:27.480",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Issue Tracking",
              "Patch"
            ],
            "url": "https://github.com/coder/coder/pull/26146"
          },
          {
            "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-v54h-cp2w-9x4g"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-522"
              },
              {
                "lang": "en",
                "value": "CWE-601"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-07-30T16:39:18Z",
      "cve": "CVE-2026-55431",
      "id": "CVE-2026-55431",
      "initial_release_date": "2026-07-30T16:39:18Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-55431",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-55431.json",
      "version": "2"
    },
    "vulnrichment": {
      "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": "2026-07-08T13:56:58.438Z",
              "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"
    }
  }
}



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.


Detection rules are retrieved from Rulezet.


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.