CVE-2026-40302Network attack vector

Reflected XSS via unescaped OAuth callback errors

Published Apr 17, 2026 · Updated Apr 17, 2026

Reflected XSS in OpenZiti zrok before 2.0.1 allows remote attackers to execute JavaScript via a crafted GitHub OAuth login URL. The publicProxy and dynamicProxy GitHub callback handlers place an invalid refreshInterval value in an error rendered by text/template without HTML escaping. A victim must open the login URL and finish GitHub OAuth; script then runs in the OAuth server origin with bounded DOM and form access.

CVSS severity6.1
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in OpenZiti zrok before 2.0.1 allows remote attackers to execute JavaScript via a crafted GitHub OAuth login URL. The publicProxy and dynamicProxy GitHub callback handlers place an invalid refreshInterval value in an error rendered by text/template without HTML escaping. A victim must open the login URL and finish GitHub OAuth; script then runs in the OAuth server origin with bounded DOM and form access.

The record

CVE
CVE-2026-40302
Published
Apr 17, 2026
Updated
Apr 17, 2026
Vendor
OpenZiti
Product
zrok
Classifications
CWE-116, CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenZiti · zrokversion=< 2.0.1

Published CVSS scores

6.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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