EUVD-2026-42147
GHSA-x9qq-2qh5-8rxf
Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Network-reachable RPC requires authenticated workspace owner (PR:L); no UI needed; impact bounded to low C/I with no availability effect.
Primary rating from Vendor (https://github.com/coder/coder).
CVSS VectorVendor: https://github.com/coder/coder
Lifecycle Timeline
1DescriptionCVE.org
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:
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!
AnalysisAI
Port-sharing policy bypass in Coder's CreateSubAgent RPC allows an authenticated workspace owner to register sub-agent apps at sharing levels exceeding the template's administrator-configured MaxPortSharingLevel, potentially exposing workspace apps as PUBLIC to unauthenticated users via wildcard app subdomains. Exploitation is gated behind authenticated workspace ownership with an agent token and requires an Enterprise deployment with both port-sharing policy enforcement and wildcard app hostnames active - making this a meaningful privilege escalation within a constrained environment rather than a broadly exploitable network flaw. No public exploit has been identified at time of analysis; vendor-released patches are available across all supported release lines.
Technical ContextAI
Coder is an open-source cloud development environment platform that provisions remote workspaces. The CreateSubAgent RPC is responsible for registering application endpoints exposed by workspace sub-agents. The vulnerability is classified as CWE-862 (Missing Authorization): the server-side handler accepted a caller-supplied app sharing level without clamping or validating it against the template's MaxPortSharingLevel policy, allowing the caller to persist a more permissive sharing level than the administrator intended. The fix clamps the sub-agent app sharing level at ingestion time to the template's configured ceiling. Affected packages are identified by CPE as pkg:go/github.com_coder_coder_v2, covering the Go module across the 2.29 ESR, 2.32, 2.33, and 2.34 release lines prior to their respective patch versions. The wildcard app hostname feature (CODER_WILDCARD_ACCESS_URL) is the mechanism through which overly-permissive sharing translates into unauthenticated external reachability.
RemediationAI
The primary remediation is to upgrade to a patched release: v2.34.2 (2.34 line), v2.33.8 (2.33 line), v2.32.7 (2.32 line), or v2.29.17 (2.29 ESR line), all available at https://github.com/coder/coder/releases. The upstream fix (PR #26061 at https://github.com/coder/coder/pull/26061) clamps the sub-agent app sharing level to the template's MaxPortSharingLevel at ingestion, preventing persistence of over-privileged sharing levels. If immediate patching is not possible, the vendor-documented workaround is to disable wildcard app hostnames by unsetting or removing the CODER_WILDCARD_ACCESS_URL environment variable; this blocks subdomain-based app routing entirely, eliminating the mechanism by which a PUBLIC-shared app becomes externally reachable - note that this will also disable legitimate wildcard app routing for all workspace apps, which may impact developer workflows that depend on per-app subdomain access.
Same weakness CWE-862 – Missing Authorization
View allSame technique Authentication Bypass
View allVendor StatusVendor
SUSE
Severity: Moderate| Product | Status |
|---|---|
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
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External POC / Exploit Code
Leaving vuln.today