CVE-2026-55434: Coder AI Bridge Memory Exhaustion (CVSS 6.5)

Technical summary

The vulnerability exists in AI Bridge provider request handlers that use `io.ReadAll` to process incoming request bodies without enforcing a maximum size limit. This allows authenticated attackers to craft requests with arbitrarily large payloads, exhausting server memory and triggering denial of service. The issue is rooted in improper resource handling (CWE-770) and requires prior authentication to the AI Bridge endpoints, limiting the attack surface to trusted or compromised internal users.

Business impact

Organizations using Coder's AI Bridge feature face potential service disruption if an authenticated user—whether intentionally malicious or compromised—sends memory-exhausting requests. This denial of service could interrupt development workflows and platform availability for teams relying on remote environment provisioning. The impact is bounded to availability; confidentiality and integrity of data are not affected by this flaw.

Affected systems

Coder versions 2.33.0 through 2.33.7 and versions 2.34.0 through 2.34.1 are vulnerable. Organizations running Coder should verify their installed version and confirm whether AI Bridge is enabled and accessible to end users. The vulnerability does not affect versions prior to 2.33.0 or patched versions 2.33.8 and 2.34.2 and later.

Exploitability

Exploitation requires valid credentials and prior authentication to Coder's AI Bridge endpoints. An attacker cannot exploit this vulnerability from the internet without first compromising or obtaining credentials for a legitimate user account. The technical barrier to exploitation is low once authenticated access is established—sending large payloads is straightforward—making this a practical concern for insider threats or scenarios where user credentials have been compromised.

Remediation

Upgrade to patched versions immediately: Coder 2.33.8 or 2.34.2 and later. These versions implement request body size limits on AI Bridge handlers, preventing memory exhaustion attacks. Apply patches during a planned maintenance window to minimize disruption. No workarounds are documented, so patching is the only mitigation path.

Patch guidance

Review your current Coder version using your deployment management or CLI tools. If running 2.33.x, upgrade to 2.33.8 or later. If running 2.34.x, upgrade to 2.34.2 or later. For production environments, stage the patch in a pre-production environment first to validate compatibility with your Terraform configurations and dependent tooling. Consult the Coder release notes for any breaking changes or configuration adjustments required during the upgrade process.

Detection guidance

Monitor Coder application logs for unusual request patterns to AI Bridge endpoints, particularly requests with exceptionally large Content-Length headers or payloads. Track server memory usage spikes coinciding with API activity. Implement alerting on memory exhaustion events or out-of-memory errors in your Coder deployment. Network-level monitoring of authenticated sessions to AI Bridge can also help identify anomalous activity from compromised accounts.

Why prioritize this

Although the CVSS score is 6.5 (Medium), organizations should prioritize this patch based on deployment context. If your team relies heavily on Coder for continuous development workflows, even brief outages cause significant productivity loss. The authentication requirement limits exposure, but insider threats and credential compromise are real scenarios. Patch within your standard maintenance cycle, accelerating if AI Bridge is widely used or if your access controls over credentials are uncertain.

Risk score, explained

The CVSS 3.1 score of 6.5 reflects a Medium severity due to the requirement for authenticated access (PR:L) and the limited impact scope of availability only (A:H, C:N, I:N). The network-accessible attack vector (AV:N) and low attack complexity (AC:L) reflect that the technical exploitation method is straightforward once authenticated. The score appropriately weights this as a concern for organizations with strict access controls, but not an emergency requiring immediate emergency response windows.

Frequently asked questions