{"id":"CVE-2026-55428","state":"PUBLISHED","title":"Coder: Route hijacking through lack of validation of agent-supplied AllowedIPs in tailnet coordinator","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, the tailnet coordinator validates that an agent's `Addresses` derive from its authenticated UUID but applies no equivalent check to `AllowedIPs`. The coordinator forwards agent-supplied `AllowedIPs` verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each `AllowedIPs` prefix against the authenticating agent's UUID just like `Addresses`. As a workaround, monitor coordinator logs for agents advertising unexpected `AllowedIPs` prefixes.","publishedAt":"2026-07-07T23:57:45.338Z","updatedAt":"2026-07-08T13:11:08.435Z","severity":{"score":8.2,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/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-wrq8-fcv5-8hvp","https://github.com/coder/coder/pull/26144","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-285","CWE-863"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55428.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55428","state":"PUBLISHED","datePublished":"2026-07-07T23:57:45.338Z","dateUpdated":"2026-07-08T13:11:08.435Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-16T21:59:57.016Z"},"containers":{"cna":{"title":"Coder: Route hijacking through lack of validation of agent-supplied AllowedIPs in tailnet coordinator","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, the tailnet coordinator validates that an agent's `Addresses` derive from its authenticated UUID but applies no equivalent check to `AllowedIPs`. The coordinator forwards agent-supplied `AllowedIPs` verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each `AllowedIPs` prefix against the authenticating agent's UUID just like `Addresses`. As a workaround, monitor coordinator logs for agents advertising unexpected `AllowedIPs` prefixes."}],"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-wrq8-fcv5-8hvp","name":"https://github.com/coder/coder/security/advisories/GHSA-wrq8-fcv5-8hvp","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/coder/coder/pull/26144","name":"https://github.com/coder/coder/pull/26144","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":8.2,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-285","lang":"en","description":"CWE-285: Improper Authorization","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863: Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-07T23:57:45.338Z"},"source":{"advisory":"GHSA-wrq8-fcv5-8hvp","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-08T13:10:59.507766Z","id":"CVE-2026-55428","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":"2026-07-08T13:11:08.435Z"}}]}}}