CVE-2026-55438: 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 ...

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.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N

EPSS Probability

0.22%

12.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-346

Affected Software

Vendor	Product	Versions
Coder	Coder	< 2.29.17
Coder	Coder	>= 2.30.0, < 2.32.7
Coder	Coder	>= 2.33.0, < 2.33.8
Coder	Coder	>= 2.34.0, < 2.34.2

References

https://github.com/coder/coder/pull/26085Issue Tracking, Patch
https://github.com/coder/coder/pull/26086Issue Tracking, Patch
https://github.com/coder/coder/releases/tag/v2.29.17Release Notes
https://github.com/coder/coder/releases/tag/v2.32.7Release Notes
https://github.com/coder/coder/releases/tag/v2.33.8Release Notes
https://github.com/coder/coder/releases/tag/v2.34.2Release Notes
https://github.com/coder/coder/security/advisories/GHSA-5wg6-jmq2-53pwPatch, Vendor Advisory

Timeline

Published: Jul 8, 2026
Last Modified: Jul 8, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-55438?

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.

How severe is CVE-2026-55438?

CVE-2026-55438 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.

How do I fix CVE-2026-55438?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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