zrok: Reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error rendering
Published Apr 17, 2026 · Updated Oct 23, 2026 · Also known as GHSA-4fxq-2x3x-6xqx, GO-2026-5118
Original summary
Normalized public record · Updated Oct 23, 2026
zrok: Reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error rendering
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
**Summary** The proxyUi template engine uses Go's text/template (which performs no HTML escaping) instead of html/template. The GitHub OAuth callback handlers in both publicProxy and dynamicProxy embed the attacker-controlled refreshInterval query parameter verbatim into an error message when time.ParseDuration fails, and render that error unescaped into HTML. An attacker can deliver a crafted login URL to a victim; after the victim completes the GitHub OAuth flow, the callback page executes arbitrary JavaScript in the OAuth server's origin.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- GHSA-4fxq-2x3x-6xqx, GO-2026-5118
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Apr 17, 2026 · Last refreshed Oct 23, 2026