{"id":"CVE-2026-55432","aliases":["GHSA-x9qq-2qh5-8rxf","GO-2026-5926"],"url":"https://o3.security/vulnerability/CVE-2026-55432","summary":"Coder's sub-agent app registration bypasses template port-sharing policy enforcement","details":"### Summary\n\nThe `CreateSubAgent` RPC did not validate a requested app sharing level against the template's `MaxPortSharingLevel` before persisting workspace apps, letting a workspace owner exceed the administrator's configured maximum.\n\n> **Note:** Exploitation requires the ability to register sub-agent apps in a workspace the attacker controls.\n\n### Impact\n\nA workspace owner with an agent token could register a sub-agent app as `PUBLIC` even when the template's `MaxPortSharingLevel` was `owner`, exposing the app to unauthenticated users via the wildcard app domain. This affected only deployments using Enterprise port-sharing policy and wildcard app hostnames and required an authenticated workspace owner with an agent token.\n\n### Patches\n\nThe fix clamps the sub-agent app sharing level to the template's `MaxPortSharingLevel`.\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\nDisable wildcard app hostnames (`CODER_WILDCARD_ACCESS_URL`) to block subdomain-based app routing.\n\n### Resources\n\n- Fix: #26061\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22452) for independently disclosing this issue!","published":"2026-07-08T00:20:24.264Z","modified":"2026-08-12T03:51:36.452914748Z","cvss":{"score":5.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"},"epss":{"score":0.00315,"percentile":0.24246,"asOf":"2026-09-13"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/coder/coder/v2","fixedVersion":"2.34.2"},{"ecosystem":"Go","name":"github.com/coder/coder/v2","fixedVersion":"2.33.8"},{"ecosystem":"Go","name":"github.com/coder/coder/v2","fixedVersion":"2.32.7"},{"ecosystem":"Go","name":"github.com/coder/coder/v2","fixedVersion":"2.29.17"}],"fix":{"url":"https://github.com/coder/coder/pull/26061","label":"coder/coder#26061"},"references":[{"type":"WEB","url":"https://github.com/coder/coder/releases/tag/v2.29.17"},{"type":"WEB","url":"https://github.com/coder/coder/releases/tag/v2.32.7"},{"type":"WEB","url":"https://github.com/coder/coder/releases/tag/v2.33.8"},{"type":"WEB","url":"https://github.com/coder/coder/releases/tag/v2.34.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55432.json"},{"type":"ADVISORY","url":"https://github.com/coder/coder/security/advisories/GHSA-x9qq-2qh5-8rxf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55432"},{"type":"FIX","url":"https://github.com/coder/coder/pull/26061"},{"type":"PACKAGE","url":"https://github.com/coder/coder"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:36.452914748Z"}}