CVE-2026-55079: Github.com/coder/coder/v2 Denial of Service Vulnerability
MODERATECVE-2026-55079 is a MODERATE (CVSS 4.9) denial of service vulnerability (CWE-789: Memory Allocation with Excessive Size Value) affecting Github.com/coder/coder/v2 libraries in the Go ecosystem. The issue involves coder's unbounded memory allocation in provisioner file upload allows authenticated denial of service. Remediation is available by upgrading affected packages to version 2.34.2, 2.32.7, 2.29.17, 2.33.8.
CVE-2026-55079 at a Glance
Security Impact
CVSS: 4.9
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-55079
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 2.32.7Upgrade github.com/coder/coder/v2 to 2.29.17Upgrade 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-2026-55079, 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-789: Memory Allocation with Excessive Size Value, where the product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to 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-2026-55079 Affected Github.com/coder/coder/v2 Versions
4 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 |
≥ 2.30.0
< 2.32.7
|
2.32.7
|
|
github.com/coder/coder/v2
|
Go |
≥ 2.24.0
< 2.29.17
|
2.29.17
|
|
github.com/coder/coder/v2
|
Go |
≥ 2.33.0
< 2.33.8
|
2.33.8
|
References
Frequently Asked Questions
What is CVE-2026-55079?
Which Github.com/coder/coder/v2 versions are affected?
What version fixes CVE-2026-55079?
Is github.com/coder/coder/v2 affected?
What is the CVSS score of CVE-2026-55079?
What CWE is associated with CVE-2026-55079?
How can I check Go dependencies for CVE-2026-55079?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-f962-qm93-mj4c",
"modified" : "2026-07-06T20:54:42Z",
"published" : "2026-07-06T20:54:41Z",
"aliases" : [ "CVE-2026-55079" ],
"summary" : "Coder's unbounded memory allocation in provisioner file upload allows authenticated denial of service",
"details" : "### Summary\n\n`NewDataBuilder` in `provisionersdk/proto/dataupload.go` allocated a byte slice using the client-supplied `FileSize` from a `DataUpload` message without an upper-bound check. Although the DRPC wire limit is 4 MiB, the `FileSize` value itself was unconstrained\n\n### Impact\n\nAn authenticated user able to reach the provisioner daemon serve endpoint could send a roughly 50-byte message declaring a huge `FileSize` (for example 1 TiB), triggering an unrecoverable Go out-of-memory abort that terminates `coderd`. This is a single-message denial of service affecting the entire deployment.\n\n### Patches\n\nThe fix validates `FileSize` against an upper bound (`MaxFileSize = 100 MiB`) before allocation.\n\nThe fix was backported to all supported release lines:\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| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |\n| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |\n\n### Workarounds\n\nRestrict access to the provisioner daemon serve endpoint to trusted provisioner daemon service accounts.\n\n### Resources\n\n- Fix: #25710\n\n### Credits\n\nCoder would like to thank Anthropic's Security Team (ANT-2026-22442) for independently disclosing this issue!",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:H/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"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/coder/coder/v2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.30.0"
}, {
"fixed" : "2.32.7"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/coder/coder/v2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.24.0"
}, {
"fixed" : "2.29.17"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/coder/coder/security/advisories/GHSA-f962-qm93-mj4c"
}, {
"type" : "WEB",
"url" : "https://github.com/coder/coder/pull/25710"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/coder/coder"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-789" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-06T20:54:41Z",
"nvd_published_at" : null
}
}