CVE-2026-55434: Github.com/coder/coder/v2 Denial of Service Vulnerability
MODERATECVE-2026-55434 is a MODERATE (CVSS 6.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Github.com/coder/coder/v2 libraries in the Go ecosystem. The issue involves coder vulnerable to denial of service via unbounded request body in ai bridge provider endpoints. Remediation is available by upgrading affected packages to version 2.34.2, 2.33.8.
CVE-2026-55434 at a Glance
Security Impact
CVSS: 6.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-55434
To remediate this vulnerability, upgrade all affected Github.com/coder/coder/v2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/coder/coder/v2 to 2.34.2Upgrade github.com/coder/coder/v2 to 2.33.8Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/coder/coder/v2How to Check if You Are Affected
To determine whether your application is affected by CVE-2026-55434, inspect your project dependencies for Github.com/coder/coder/v2:
inspect dependencies for github.com/coder/coder/v2Analyze the terminal output to locate any version of Github.com/coder/coder/v2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.34.2), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where 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. In Github.com/coder/coder/v2, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-55434 Affected Github.com/coder/coder/v2 Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/coder/coder/v2
|
Go |
≥ 2.34.0
< 2.34.2
|
2.34.2
|
|
github.com/coder/coder/v2
|
Go |
≥ 2.33.0
< 2.33.8
|
2.33.8
|
References
Frequently Asked Questions
What is CVE-2026-55434?
Which Github.com/coder/coder/v2 versions are affected?
What version fixes CVE-2026-55434?
Is github.com/coder/coder/v2 affected?
What is the CVSS score of CVE-2026-55434?
What CWE is associated with CVE-2026-55434?
How can I check Go dependencies for CVE-2026-55434?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-f5vp-w269-392g",
"modified" : "2026-07-07T22:17:48Z",
"published" : "2026-07-06T21:10:13Z",
"aliases" : [ "CVE-2026-55434" ],
"summary" : "Coder vulnerable to denial of service via unbounded request body in AI Bridge provider endpoints",
"details" : "### Summary\n\nAI 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.\n\n> **Note:** Exploitation requires authenticated access to the AI Bridge endpoints and the impact is limited to availability (denial of service).\n\n### Impact\n\nAn 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.\n\n### Patches\n\nThe 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.\n\nThe fix is available in the following releases:\n\n| Release line | Patched version |\n|---|---|\n| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |\n| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |\n\n### Workarounds\n\nNone.\n\n### Resources\n\n- Fix: #26164\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22443) for independently disclosing this issue!",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/coder/coder/v2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.34.0"
}, {
"fixed" : "2.34.2"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/coder/coder/v2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.33.0"
}, {
"fixed" : "2.33.8"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/coder/coder/security/advisories/GHSA-f5vp-w269-392g"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-55434"
}, {
"type" : "WEB",
"url" : "https://github.com/coder/coder/pull/26164"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/coder/coder"
}, {
"type" : "WEB",
"url" : "https://github.com/coder/coder/releases/tag/v2.33.8"
}, {
"type" : "WEB",
"url" : "https://github.com/coder/coder/releases/tag/v2.34.2"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-770" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-06T21:10:13Z",
"nvd_published_at" : "2026-07-07T21:17:27Z"
}
}