GHSA-x9qq-2qh5-8rxf Coder's sub-agent app registration bypasses template port-sharing policy enforcement

• Go github.com/coder/coder/v2: >= 2.34.0, < 2.34.2 → fixed in 2.34.2 • Go github.com/coder/coder/v2: >= 2.33.0, < 2.33.8 → fixed in 2.33.8 • Go github.com/coder/coder/v2: >= 2.30.0, < 2.32.7 → fixed in 2.32.7 • Go github.com/coder/coder/v2: < 2.29.17 → fixed in 2.29.17

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 | | 2.33 | v2.33.8 | | 2.32 | v2.32.7 | | 2.29 (ESR) | 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!