CVE-2026-55432Medium· 5.4▾ SunlitCoder's sub-agent app registration bypasses template port-sharing policy enforcement
▾ Sunlit zone — Low / medium · no exploitation signal
impact 29.7 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.3%
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.
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.
The fix clamps the sub-agent app sharing level to the template's MaxPortSharingLevel.
The fix was backported to all supported release lines:
Disable wildcard app hostnames (CODER_WILDCARD_ACCESS_URL) to block subdomain-based app routing.
Coder would like to thank Anthropic's Security Team (ANT-2026-22452) for independently disclosing this issue!
github.com/coder/coder/v2 >= 2.34.0, < 2.34.2github.com/coder/coder/v2 >= 2.33.0, < 2.33.8github.com/coder/coder/v2 >= 2.30.0, < 2.32.7github.com/coder/coder/v2 < 2.29.17Upgrade to a patched release:
github.com/coder/coder/v2 2.34.2github.com/coder/coder/v2 2.33.8github.com/coder/coder/v2 2.32.7github.com/coder/coder/v2 2.29.17Connected by shared product, vendor, weakness, or advisory.
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