CVE-2026-55436: Coder's AI Bridge Proxy skips TLS certificate verification in default configuration
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 HTTPPROXY and HTTPSPROXY, 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!
Other sources
Coder allows organizations to provision remote development environments via Terraform. Starting in version 2.30.0 and prior to versions 2.32.7, 2.33.8, and 2.34.2, 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. 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. The fix in versions 2.32.7, 2.33.8, and 2.34.2 applies the secure transport (TLS 1.2 or higher using system root CAs) unconditionally. As a workaround, 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).
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go/github.com/coder/coder/v2to a version that resolves this vulnerability.Fixed in 2.32.7 - Upgrade
Upgrade
go/github.com/coder/coder/v2to a version that resolves this vulnerability.Fixed in 2.33.8 - Upgrade
Upgrade
go/github.com/coder/coder/v2to a version that resolves this vulnerability.Fixed in 2.34.2 - Upgrade
Upgrade
Coder AI Bridge Proxy (aibridgeproxyd)to a version that resolves this vulnerability.Fixed in 2.32.7Patch Fix: #26131 - Upgrade
Upgrade
Coder AI Bridge Proxy (aibridgeproxyd)to a version that resolves this vulnerability.Fixed in 2.33.8Patch Fix: #26131 - Upgrade
Upgrade
Coder AI Bridge Proxy (aibridgeproxyd)to a version that resolves this vulnerability.Fixed in 2.34.2Patch Fix: #26131 - Configuration
Do not run the AI Bridge Proxy with default behavior that skips TLS certificate verification; apply the fix so the secure transport (TLS 1.2 or higher using system root CAs) is applied unconditionally.
AI Bridge Proxy (aibridgeproxyd) TLS certificate verification / InsecureSkipVerify = verification enabled (set InsecureSkipVerify: false) - Compensating control
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).
Event History
Frequently Asked Questions
What is the severity of CVE-2026-55436?
The severity of CVE-2026-55436 is rated high with a score of 7.4.
What does CVE-2026-55436 affect?
CVE-2026-55436 affects the AI Bridge Proxy component in the go/github.com/coder/coder/v2 software.
How do I fix CVE-2026-55436?
To fix CVE-2026-55436, ensure that the transport settings do not use 'InsecureSkipVerify: true' in the default configuration.
What impact does CVE-2026-55436 have on my system?
CVE-2026-55436 can potentially expose sensitive data as it allows insecure outbound HTTPS communications by default.
When was CVE-2026-55436 published?
CVE-2026-55436 was published on July 6, 2026.