zrok has reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error rendering

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Summary

CVECVE-2026-40302
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-17 21:16:34 UTC
Updated2026-04-17 21:16:34 UTC
Descriptionzrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, 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. Version 2.0.1 patches the issue.

Risk And Classification

Primary CVSS: v3.1 6.1 MEDIUM from [email protected]

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

Problem Types: CWE-79 | CWE-116 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | CWE-116 CWE-116: Improper Encoding or Escaping of Output

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
3.1CNADECLARED6.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Openziti Zrok affected < 2.0.1 Not specified

References

ReferenceSourceLinkTags
github.com/openziti/zrok/releases/tag/v2.0.1 [email protected] github.com
github.com/openziti/zrok/security/advisories/GHSA-4fxq-2x3x-6xqx [email protected] github.com
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