{"id":"GHSA-4fxq-2x3x-6xqx","revision":"fa22a4e970014e74b53531a760b792fd","records":[{"revision":"fa22a4e970014e74b53531a760b792fd","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-4fxq-2x3x-6xqx","aliases":["CVE-2026-40302","GO-2026-5118"],"title":"zrok: Reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error rendering","description":"**Summary**\nThe 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.\n\n- Attack Vector: Network — the attack is delivered as a crafted URL over the internet.\n- Attack Complexity: Low — no race conditions or special environment prerequisites.\n- Privileges Required: None — the attacker needs no account on the zrok instance.\n- User Interaction: Required — the victim must click the crafted link and complete the GitHub OAuth flow.\n- Scope: Changed — the injected script executes in the OAuth server's origin, not the victim's share origin.\n- Confidentiality Impact: Low — the script runs in the OAuth server origin after a failed flow; no session cookie is set at this point, limiting what can be exfiltrated to what is visible in the DOM and what can be requested from the OAuth server.\n- Integrity Impact: Low — the script can initiate new OAuth flows or submit forms on behalf of the victim in the OAuth server origin.\n- Availability Impact: None.\n\n**Affected Components**\n\n- endpoints/proxyUi/template.go — init() / WriteTemplate (lines 8, 18, 99) — text/template used for HTML rendering\n- endpoints/proxyUi/template.html — line 119 — {{ .Error }} in HTML without escaping\n- endpoints/publicProxy/providerGithub.go — login callback closure (lines 93, 128, 130)\n- endpoints/dynamicProxy/providerGithub.go — loginHandler() (lines 110, 146, 148)","state":0,"publishedAt":"2026-04-16T21:08:55+00:00","modifiedAt":"2026-06-25T18:56:29.3235236+00:00","affected":[{"ecosystem":"Go","name":"github.com/openziti/zrok","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"last_affected","version":"1.1.11"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"github.com/openziti/zrok/v2","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.0.1"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/openziti/zrok/security/advisories/GHSA-4fxq-2x3x-6xqx","https://nvd.nist.gov/vuln/detail/CVE-2026-40302","https://github.com/openziti/zrok","https://github.com/openziti/zrok/releases/tag/v2.0.1"],"sourceUrl":"https://github.com/advisories/GHSA-4fxq-2x3x-6xqx","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-4fxq-2x3x-6xqx","identifiers":["GHSA-4fxq-2x3x-6xqx","CVE-2026-40302","GO-2026-5118"]},"retained":false,"historicalAffected":[]}],"coverage":[]}