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Coder's AI Bridge Proxy skips TLS certificate verification in default configuration

High severity GitHub Reviewed Published Jun 12, 2026 in coder/coder

Package

gomod github.com/coder/coder/v2 (Go)

Affected versions

>= 2.34.0, < 2.34.2
>= 2.33.0, < 2.33.8
>= 2.30.0, < 2.32.7

Patched versions

2.34.2
2.33.8
2.32.7

Description

Summary

The AI Bridge Proxy (aibridgeproxyd) created a goproxy server whose default transport set InsecureSkipVerify: true and only assigned a secure transport when an upstream proxy was configured. In the default configuration (no upstream proxy), outbound HTTPS to the Coder access URL accepted any TLS certificate.

Note: Practical exploitation requires an on-path (man-in-the-middle) position between the AI Bridge Proxy and the Coder server. Deployments where they are co-located over loopback are effectively unaffected.

Impact

An attacker positioned between the proxy and the Coder server, via ARP spoofing, DNS poisoning or control of proxy environment variables, could intercept injected Coder session tokens, user-supplied provider API keys (BYOK) and full request and response bodies including prompts and completions. The default transport also honored HTTP_PROXY and HTTPS_PROXY, allowing environment-based traffic redirection.

Patches

The fix applies the secure transport (TLS 1.2 or higher using system root CAs) unconditionally. The AI Bridge Proxy was introduced in v2.30.0. Earlier release lines including the v2.29 ESR line are not affected.

The fix is available in the following releases:

Release line Patched version
2.34 v2.34.2
2.33 v2.33.8
2.32 v2.32.7

Workarounds

Ensure the Coder access URL uses a trusted certificate and secure the network path between the AI Bridge Proxy and the Coder server (for example, loopback or mTLS).

Resources

  • Fix: #26131

Credits

Coder would like to thank Anthropic's Security Team (ANT-2026-22455) for independently disclosing this issue!

References

@jdomeracki-coder jdomeracki-coder published to coder/coder Jun 12, 2026
Published to the GitHub Advisory Database Jul 6, 2026
Reviewed Jul 6, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(17th percentile)

Weaknesses

Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate. Learn more on MITRE.

CVE ID

CVE-2026-55436

GHSA ID

GHSA-84rm-42xw-mx52

Source code

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