GHSA-x9qq-2qh5-8rxf

Coder's sub-agent app registration bypasses template port-sharing policy enforcement

### Summary The `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. > **Note:** Exploitation requires the ability to register sub-agent apps in a workspace the attacker controls. ### Impact A 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. ### Patches The fix clamps the sub-agent app sharing level to the template's `MaxPortSharingLevel`. The fix was backported to all supported release lines: | Release line | Patched version | |---|---| | 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) | | 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) | | 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) | | 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) | ### Workarounds Disable wildcard app hostnames (`CODER_WILDCARD_ACCESS_URL`) to block subdomain-based app routing. ### Resources - Fix: #26061 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22452) for independently disclosing this issue!