What is GHSA-h58c-xccx-75m3?

GHSA-h58c-xccx-75m3 is a security advisory published by GitHub Security Advisories with Low severity. Coder: Stored HTML injection via unescaped ApplicationName and LogoURL appearance settings

Why does GHSA-h58c-xccx-75m3 have no CVE ID yet?

GitHub Security Advisories published this advisory directly to customers before NVD assigned a CVE ID. This is the embargo-window disclosure pattern — vendors notify customers on day 0; NVD's public record follows days to weeks later.

What is the CVSS v3 score of GHSA-h58c-xccx-75m3?

GHSA-h58c-xccx-75m3 has a CVSS v3 base score of 3.4, published by GitHub Security Advisories.

Which products are affected by GHSA-h58c-xccx-75m3?

GHSA-h58c-xccx-75m3 affects 4 products, including: go/github.com/coder/coder/v2:\u003e= 2.34.0, \u003c 2.34.2; go/github.com/coder/coder/v2:\u003e= 2.33.0, \u003c 2.33.8; go/github.com/coder/coder/v2:\u003e= 2.30.0, \u003c 2.32.7; go/github.com/coder/coder/v2:\u003c 2.29.17.

GHSA-h58c-xccx-75m3LowCVSS 3.4Disclosed before NVD

Coder: Stored HTML injection via unescaped ApplicationName and LogoURL appearance settings

Vendor

GitHub Security Advisories

Published

August 20, 2026

Last Modified

August 20, 2026

📋 Description

Summary

The ApplicationName and LogoURL appearance settings were rendered into HTML output without sufficient escaping which let a highly privileged Owner-role user inject HTML into the Coder dashboard and SMTP notification emails.

Note: Exploitation requires the Owner role which already holds full administrative control of the deployment so practical impact is limited.

Impact

An Owner-role user could store HTML markup in the ApplicationName or LogoURL appearance settings that later rendered in the dashboard and in SMTP notification emails which results in stored HTML injection against other users of the deployment. Exploitation requires the highly privileged Owner role.

Patches

The fix escapes the ApplicationName and LogoURL appearance values in HTML output before rendering.

The fix was backported to all supported release lines:

| Release line | Patched version | |---|---| | 2.34 | v2.34.2 | | 2.33 | v2.33.8 | | 2.32 | v2.32.7 | | 2.29 (ESR) | v2.29.17 |

Workarounds

Restrict the Owner role to trusted administrators.

References

Fix: #25804

Credits

We'd like to thank Anthropic's Security Team (ANT-2026-22453) for independently disclosing this issue!

🎯 Affected products4

go/github.com/coder/coder/v2:>= 2.34.0, < 2.34.2
go/github.com/coder/coder/v2:>= 2.33.0, < 2.33.8
go/github.com/coder/coder/v2:>= 2.30.0, < 2.32.7
go/github.com/coder/coder/v2:< 2.29.17