CVE-2026-55432 Coder's sub-agent app registration bypasses template port-sharing policy enforcement

Medium 5.4 Published Updated

Workspace owners can bypass administrator-defined port sharing limits by registering sub-agent apps with excessive sharing levels.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-55432?

CVE-2026-55432 is a medium-severity missing authorization vulnerability in coder, published on 8 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, 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. Exploitation requires the ability to register sub-agent apps in a workspace the attacker controls. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2clamps the sub-agent app sharing level to the template's `MaxPortSharingLevel`. As a workaround, disable wildcard app hostnames (`CODER_WILDCARD_ACCESS_URL`) to block subdomain-based app routing.

Weakness: CWE-862

Which versions are affected by CVE-2026-55432?

10 open source packages ship an affected version, including github.com/coder/coder/v2 and github.com/coder/coder. It affects 1 product.

PackageAffectedFixed in
github.com/coder/coder/v2 GoAll versions2.29.17, 2.32.7, 2.33.8, 2.34.2
github.com/coder/coder/v2 GoAll versions2.29.17
github.com/coder/coder/v2 GoAll versions2.29.17
github.com/coder/coder/v2 GoFrom 2.30.02.32.7
github.com/coder/coder/v2 GoFrom 2.30.02.32.7
github.com/coder/coder/v2 GoFrom 2.33.02.33.8
4 more packages
github.com/coder/coder/v2 GoFrom 2.33.02.33.8
github.com/coder/coder/v2 GoFrom 2.34.02.34.2
github.com/coder/coder/v2 GoFrom 2.34.02.34.2
github.com/coder/coder GoAll versionsNone

Products include Coder Coder.

How do I fix CVE-2026-55432?

Upgrade github.com/coder/coder/v2 to a fixed version for your release line: 2.29.17, 2.32.7, 2.33.8 or 2.34.2.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-55432 being exploited?

There is no known exploitation of CVE-2026-55432 in the wild and no public exploit code.

Sources

Also known as GHSA-x9qq-2qh5-8rxf, GO-2026-5926.

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