CVE-2026-55434 Coder vulnerability
Coder allows organizations to provision remote development environments via Terraform. Starting in version 2.33.0 and prior to versions 2.33.8 and 2.34.2, AI Bridge provider handlers read request bodies with `io.ReadAll` without a maximum size so an authenticated user with AI Bridge access could send an arbitrarily large body and exhaust memory. Exploitation requires authenticated access to the AI Bridge endpoints and the impact is limited to availability (denial of service). Versions 2.33.8 and 2.34.2 patch the issue. No known workarounds are available.
Quick answer
Coder should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- >=2.34.0 <2.34.2
- >=2.33.0 <2.33.8
Fixed versions
- 2.33.8
- 2.34.2
How to fix it
CVE-2026-55434 affects Coder remote development deployments where AI Bridge provider handlers can read unbounded request bodies, allowing an authenticated AI Bridge user to exhaust Coderd memory. Prioritize internet-facing, shared, or multi-tenant Coder environments because compromise can affect developer workspaces, identity flows, tokens, or control-plane availability depending on the issue. Upgrade to Coder 2.33.8 and 2.34.2, or a later supported release on the relevant branch, because those are the vendor-supported patched versions. Patch urgently where AI Bridge is enabled; if patching is delayed, reduce exposure by limiting AI Bridge access and proxy request sizes, while treating that as a compensating control because the advisory lists no official workaround.
- Inventory all Coder servers, workspace proxies, provisioner daemons, AI Bridge components, templates, and CLI installations across production, staging, and developer environments.
- Identify affected Coder versions and compare every deployment with the fixed releases for CVE-2026-55434: 2.33.8 and 2.34.2.
- Upgrade Coder servers and related components to the patched release for the installed branch, then roll updated CLI or automation binaries where they are part of the affected workflow.
- Patch urgently where AI Bridge is enabled; if patching is delayed, reduce exposure by limiting AI Bridge access and proxy request sizes, while treating that as a compensating control because the advisory lists no official workaround.
- Review Coder role bindings, OIDC settings, API keys, template parameters, provisioner access, workspace app exposure, and reverse proxy rules for unnecessary trust or public reachability.
- Review Coder audit logs, reverse proxy logs, provisioner logs, and workspace events for suspicious requests matching the affected endpoint or workflow.
- If exploitation or credential exposure is suspected, revoke affected sessions, rotate API keys and workspace tokens, preserve audit evidence, and rebuild workspaces or hosts whose integrity cannot be trusted.
Scan now. Google sign-in is only needed to unlock fix guidance.
Verify the fix
- Confirm every affected Coder component reports a patched version for CVE-2026-55434: 2.33.8 and 2.34.2, or a later supported release.
- Confirm AI Bridge provider and session request bodies are capped before they are read into memory.
- Confirm temporary restrictions, role changes, OIDC settings, proxy ACLs, and API-key revocations match the intended least-privilege policy.
- Review logs after patching to confirm exploit attempts are blocked or fail safely without exposing credentials, internal network details, or control-plane availability.
- Document patched versions, configuration changes, remaining exceptions, and evidence, then rerun Fixnx or the relevant vulnerability scan where applicable.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-55434?
Coder versions listed as affected should be reviewed: >=2.34.0 <2.34.2, >=2.33.0 <2.33.8.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.