Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.

No CVSS v4.0

Attack Vector Network

Attack Complexity High

Privileges Required Low

Scope Changed

Confidentiality Impact High

Integrity Impact None

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
coder coder affected
Version Status Constraints
>= 2.34.0, < 2.34.2 affected —
>= 2.33.0, < 2.33.8 affected —
>= 2.30.0, < 2.32.7 affected —
< 2.29.17 affected —

No data.

No data.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-5wg6-jmq2-53pw Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/coder/coder/pull/26085 cve-icon
https://github.com/coder/coder/pull/26086 cve-icon
https://github.com/coder/coder/releases/tag/v2.29.17 cve-icon
https://github.com/coder/coder/releases/tag/v2.32.7 cve-icon
https://github.com/coder/coder/releases/tag/v2.33.8 cve-icon
https://github.com/coder/coder/releases/tag/v2.34.2 cve-icon
https://github.com/coder/coder/security/advisories/GHSA-5wg6-jmq2-53pw cve-icon
History

Wed, 08 Jul 2026 03:15:00 +0000

Type Values Removed Values Added
First Time appeared Coder
Coder coder
Vendors & Products Coder
Coder coder

Wed, 08 Jul 2026 01:00:00 +0000

Type Values Removed Values Added
Description Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, Coder's subdomain-based workspace app proxy allowed the same-owner CORS check to be bypassed. When a workspace-name subdomain segment parsed as a UUID, the workspace was resolved by ID without confirming the URL's username matched the real owner, while the CORS middleware trusted the unverified username in the hostname. Practical exploitation requires subdomain app routing (wildcard hostname) enabled and a victim who visits the attacker's crafted app URL while authenticated. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 validates the subdomain username against the resolved workspace's actual owner and bases the same-owner CORS decision on the authoritative owner identity. No known workarounds are available.
Title Coder's workspace app CORS origin check can be bypassed via UUID-based subdomain spoofing
Weaknesses CWE-346
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-08T00:31:20.573Z

Reserved: 2026-06-16T21:59:57.017Z

Link: CVE-2026-55438

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-08T03:00:04Z

Weaknesses