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Fix token type hint injection vulnerability in TokenIntrospectionEndpoint #46752

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Merged
ahus1 merged 2 commits into from
Mar 3, 2026
Merged

Fix token type hint injection vulnerability in TokenIntrospectionEndpoint #46752

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3dc9039
Fix token type hint injection vulnerability in TokenIntrospectionEndp…
RepoRonin Mar 2, 2026
663d04d
Added test
ahus1 Mar 3, 2026
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4 changes: 3 additions & 1 deletion services/src/main/java/org/keycloak/protocol/oidc/endpoints/TokenIntrospectionEndpoint.java
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,9 @@ public Response introspect() {
TokenIntrospectionProvider provider = this.session.getProvider(TokenIntrospectionProvider.class, tokenTypeHint);

if (provider == null) {
throw throwErrorResponseException(Errors.INVALID_REQUEST, "Unsupported token type [" + tokenTypeHint + "].", Status.BAD_REQUEST);
event.detail(Details.TOKEN_TYPE, tokenTypeHint);
event.error(Errors.INVALID_REQUEST);
throw throwErrorResponseException(Errors.INVALID_REQUEST, "Unsupported token type.", Status.BAD_REQUEST);
}

try {
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40 changes: 40 additions & 0 deletions ...uillian/tests/base/src/test/java/org/keycloak/testsuite/oauth/TokenIntrospectionTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import org.keycloak.OAuthErrorException;
import org.keycloak.admin.client.resource.ClientScopesResource;
import org.keycloak.crypto.Algorithm;
import org.keycloak.events.Details;
import org.keycloak.events.Errors;
import org.keycloak.events.EventType;
import org.keycloak.jose.jws.JWSInput;
Expand Down Expand Up @@ -579,6 +580,22 @@ public void testIntrospectionRequestParamsMoreThanOnce() throws Exception {
assertEquals(OAuthErrorException.INVALID_REQUEST, errorRep.getError());
}

@Test
public void testIntrospectionUnknownType() throws Exception {
events.clear();
String tokenResponse = introspectUnknownTokenType("confidential-cli", "secret1", "xxx");

OAuth2ErrorRepresentation errorRep = JsonSerialization.readValue(tokenResponse, OAuth2ErrorRepresentation.class);
assertEquals("Unsupported token type.", errorRep.getErrorDescription());
assertEquals(OAuthErrorException.INVALID_REQUEST, errorRep.getError());
events.expect(EventType.INTROSPECT_TOKEN)
.client("confidential-cli")
.user((String) null)
.detail(Details.TOKEN_TYPE, "unknown")
.error(Errors.INVALID_REQUEST)
.assertEvent();
}

@Test
public void testIntrospectRevokeRefreshToken() throws Exception {
RealmRepresentation realm = adminClient.realm(oauth.getRealm()).toRepresentation();
Expand Down Expand Up @@ -643,6 +660,29 @@ public void testIntrospectRefreshTokenAfterRefreshTokenRequest() throws Exceptio
}
}

private String introspectUnknownTokenType(String clientId, String clientSecret, String tokenToIntrospect) {
HttpPost post = new HttpPost(oauth.getEndpoints().getIntrospection());

String authorization = BasicAuthHelper.createHeader(clientId, clientSecret);
post.setHeader("Authorization", authorization);

List<NameValuePair> parameters = new LinkedList<>();

parameters.add(new BasicNameValuePair("token", tokenToIntrospect));
parameters.add(new BasicNameValuePair("token_type_hint", "unknown"));

UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters, StandardCharsets.UTF_8);
post.setEntity(formEntity);

try (CloseableHttpResponse response = HttpClientBuilder.create().build().execute(post)) {
ByteArrayOutputStream out = new ByteArrayOutputStream();
response.getEntity().writeTo(out);
return new String(out.toByteArray());
} catch (Exception e) {
throw new RuntimeException("Failed to retrieve access token", e);
}
}

private String introspectAccessTokenWithDuplicateParams(String clientId, String clientSecret, String tokenToIntrospect) {
HttpPost post = new HttpPost(oauth.getEndpoints().getIntrospection());

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