CVE-2026-46354

CVE-2026-46354 is a critical-severity security vulnerability in github.com/coder/coder/v2 (go), affecting versions >= 2.33.0-rc.0, < 2.33.3. It is fixed in 2.33.3, 2.32.2, 2.31.12, 2.30.8, 2.29.13, 2.24.5.

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Summary

Coder: PKCS#7 signature bypass in Azure instance identity allows unauthenticated agent token theft

azureidentity.Validate() verifies that the PKCS#7 signer certificate chains to a trusted Azure CA but never verifies the PKCS#7 signature itself. An attacker can embed a legitimate Azure certificate alongside arbitrary content e.g. {"vmId":"<target>"} and the forged vmId will be accepted returning the victim workspace agent's session token.

No authentication is required. The attacker only needs to know a target VM's vmId which is a UUIDv4.

that's a practical limitation which would typically require prior access to be exploited

Root Cause

In unpatched Coder releases the signature over the PKCS#7 content is not validated - only the signing certificate is checked.

Attack Path Diagram

Affected Versions

All versions of Coder v2 are affected.

Workarounds

If unable to patch we recommend immediately reconfiguring any Azure templates to use token authentication rather than azure-instance-identity until the patch is released and you are fully upgraded.

  1. Modify the coder_agent.auth value to be token.
  2. Add CODER_AGENT_TOKEN=${coder_agent.main.token} to the set of environment variables for the Coder Workspace Agent initialization script.

Recognition

We'd like to thank Ben Tran of calif.io and Anthropic’s Security Team (ANT-2026-22445) for independently disclosing this issue!

Impact

An attacker on any Azure VM or with access to a publicly available Azure IMDS certificate from CT logs can:

  1. Steal an agent session token by sending a forged PKCS#7 envelope to POST /api/v2/workspaceagents/azure-instance-identity which is unauthenticated.
  2. With the stolen token access:
    • Git SSH private key via GET /workspaceagents/me/gitsshkey: push to repositories and impersonate the workspace owner.
    • OAuth access tokens via GET /workspaceagents/me/external-auth: GitHub, GitLab, and Bitbucket tokens in plaintext.
    • Workspace secrets via the agent manifest: environment variables, file paths, and API keys.

CVE-2026-46354 has a CVSS score of 9.1 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.33.3, 2.32.2, 2.31.12, 2.30.8, 2.29.13, 2.24.5); upgrading removes the vulnerable code path.

Affected versions

github.com/coder/coder/v2 (>= 2.33.0-rc.0, < 2.33.3) github.com/coder/coder/v2 (>= 2.32.0-rc.0, < 2.32.2) github.com/coder/coder/v2 (>= 2.31.0, < 2.31.12) github.com/coder/coder/v2 (>= 2.30.0, < 2.30.8) github.com/coder/coder/v2 (>= 2.29.0, < 2.29.13) github.com/coder/coder/v2 (< 2.24.5) github.com/coder/coder (<= 0.27.3)

Security releases

github.com/coder/coder/v2 → 2.33.3 (go) github.com/coder/coder/v2 → 2.32.2 (go) github.com/coder/coder/v2 → 2.31.12 (go) github.com/coder/coder/v2 → 2.30.8 (go) github.com/coder/coder/v2 → 2.29.13 (go) github.com/coder/coder/v2 → 2.24.5 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Fixed in #25286

The fix was backported to all supported release lines:

Patched Versions
v2.33.3
v2.32.2
v2.31.12
v2.30.8
v2.29.13
v2.24.5

Frequently Asked Questions

  1. What is CVE-2026-46354? CVE-2026-46354 is a critical-severity security vulnerability in github.com/coder/coder/v2 (go), affecting versions >= 2.33.0-rc.0, < 2.33.3. It is fixed in 2.33.3, 2.32.2, 2.31.12, 2.30.8, 2.29.13, 2.24.5.
  2. How severe is CVE-2026-46354? CVE-2026-46354 has a CVSS score of 9.1 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which packages are affected by CVE-2026-46354?
    • github.com/coder/coder/v2 (go) (versions >= 2.33.0-rc.0, < 2.33.3)
    • github.com/coder/coder (go) (versions <= 0.27.3)
  4. Is there a fix for CVE-2026-46354? Yes. CVE-2026-46354 is fixed in 2.33.3, 2.32.2, 2.31.12, 2.30.8, 2.29.13, 2.24.5. Upgrade to this version or later.
  5. Is CVE-2026-46354 exploitable, and should I be worried? Whether CVE-2026-46354 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-46354 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-46354?
    • Upgrade github.com/coder/coder/v2 to 2.33.3 or later
    • Upgrade github.com/coder/coder/v2 to 2.32.2 or later
    • Upgrade github.com/coder/coder/v2 to 2.31.12 or later
    • Upgrade github.com/coder/coder/v2 to 2.30.8 or later
    • Upgrade github.com/coder/coder/v2 to 2.29.13 or later
    • Upgrade github.com/coder/coder/v2 to 2.24.5 or later

Other vulnerabilities in github.com/coder/coder/v2

CVE-IDSeverityPackage summary
GHSA-QRWJ-VH9X-GW5VHighgithub.com/coder/coder/v2: Coder's workspace agent API insecure redirect handling allowed cross-agent file read and writeCVE-2026-55438Mediumgithub.com/coder/coder/v2: Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofingCVE-2026-55437Mediumgithub.com/coder/coder/v2: Coder vulnerable to stored HTML injection via workspace agent logs in AgentLogLine componentCVE-2026-55436Highgithub.com/coder/coder/v2: Coder's AI Bridge Proxy skips TLS certificate verification in default configurationCVE-2026-55435Mediumgithub.com/coder/coder/v2: Suspended Coder users retain access to AI Bridge LLM proxy endpoints

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