{"id":"CVE-2026-55431","state":"PUBLISHED","title":"Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps","description":"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.","publishedAt":"2026-07-08T00:10:49.165Z","updatedAt":"2026-07-08T13:57:02.059Z","severity":{"score":7.7,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["coder coder"],"affected":[{"vendor":"coder","product":"coder","versions":[{"version":">= 2.34.0, < 2.34.2","status":"affected"},{"version":">= 2.33.0, < 2.33.8","status":"affected"},{"version":">= 2.30.0, < 2.32.7","status":"affected"},{"version":"< 2.29.17","status":"affected"}]}],"references":["https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g","https://github.com/coder/coder/pull/26146","https://github.com/coder/coder/releases/tag/v2.29.17","https://github.com/coder/coder/releases/tag/v2.32.7","https://github.com/coder/coder/releases/tag/v2.33.8","https://github.com/coder/coder/releases/tag/v2.34.2"],"weaknesses":["CWE-522","CWE-601"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55431.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55431","state":"PUBLISHED","datePublished":"2026-07-08T00:10:49.165Z","dateUpdated":"2026-07-08T13:57:02.059Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T21:59:57.017Z"},"containers":{"cna":{"title":"Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps","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 `$SESSION_TOKEN` placeholder the CLI replaces it with the user's real session token before handing the URL to the OS open handler. Practical exploitation requires the victim to run `coder open app` against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 applies a URL-scheme allowlist in the CLI and limits `$SESSION_TOKEN` substitution to trusted destinations like the web frontend. As a workaround, avoid running `coder open app` for untrusted workspaces."}],"affected":[{"vendor":"coder","product":"coder","versions":[{"version":">= 2.34.0, < 2.34.2","status":"affected"},{"version":">= 2.33.0, < 2.33.8","status":"affected"},{"version":">= 2.30.0, < 2.32.7","status":"affected"},{"version":"< 2.29.17","status":"affected"}]}],"references":[{"url":"https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g","name":"https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/coder/coder/pull/26146","name":"https://github.com/coder/coder/pull/26146","tags":["x_refsource_MISC"]},{"url":"https://github.com/coder/coder/releases/tag/v2.29.17","name":"https://github.com/coder/coder/releases/tag/v2.29.17","tags":["x_refsource_MISC"]},{"url":"https://github.com/coder/coder/releases/tag/v2.32.7","name":"https://github.com/coder/coder/releases/tag/v2.32.7","tags":["x_refsource_MISC"]},{"url":"https://github.com/coder/coder/releases/tag/v2.33.8","name":"https://github.com/coder/coder/releases/tag/v2.33.8","tags":["x_refsource_MISC"]},{"url":"https://github.com/coder/coder/releases/tag/v2.34.2","name":"https://github.com/coder/coder/releases/tag/v2.34.2","tags":["x_refsource_MISC"]}],"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","lang":"en","description":"CWE-522: Insufficiently Protected Credentials","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-601","lang":"en","description":"CWE-601: URL Redirection to Untrusted Site ('Open Redirect')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-08T00:10:49.165Z"},"source":{"advisory":"GHSA-v54h-cp2w-9x4g","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-08T13:56:53.370657Z","id":"CVE-2026-55431","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-08T13:57:02.059Z"}}]}}}