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Coder vulnerable to denial of service via unbounded request body in AI Bridge provider endpoints

Moderate severity GitHub Reviewed Published Jun 12, 2026 in coder/coder • Updated Jul 7, 2026

Package

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

Affected versions

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

Patched versions

2.34.2
2.33.8

Description

Summary

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.

Note: Exploitation requires authenticated access to the AI Bridge endpoints and the impact is limited to availability (denial of service).

Impact

An authenticated member-level user could POST a very large or chunked body to an AI Bridge provider endpoint such as /api/v2/aibridge/anthropic/v1/messages, growing heap memory until the operating system terminates the process. Because AI Bridge runs in-process with coderd, this crashes the entire control plane, including the API, workspace coordinator and DERP relay. It requires an authenticated user and the AI Bridge feature enabled.

Patches

The fix applies http.MaxBytesReader or an equivalent cap before reading provider and session request bodies. The affected AI Bridge provider endpoints exist only on the v2.33 and v2.34 lines. Earlier release lines 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

Workarounds

None.

Resources

  • Fix: #26164

Credits

Coder would like to thank Anthropic's Security Team (ANT-2026-22443) 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
Published by the National Vulnerability Database Jul 7, 2026
Last updated Jul 7, 2026

Severity

Moderate

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
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.
(42nd percentile)

Weaknesses

Allocation of Resources Without Limits or Throttling

The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. Learn more on MITRE.

CVE ID

CVE-2026-55434

GHSA ID

GHSA-f5vp-w269-392g

Source code

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