From e44df496cec4f5b5420134a8621e9266859e2536 Mon Sep 17 00:00:00 2001
From: jimmychakkalakal <47317106+jimmychakkalakal@users.noreply.github.com>
Date: Thu, 18 Jun 2026 15:04:12 +0000
Subject: [PATCH] Reject redirect URIs containing pre-loaded OIDC response parameters (#49959)
---
src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
index 4e4ad6a..d367deb 100644
--- a/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
+++ b/src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java
@@ -23,11 +23,14 @@
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
+import java.util.Locale;
import java.util.Set;
import java.util.TreeSet;
import java.util.regex.Pattern;
+import org.keycloak.OAuth2Constants;
import org.keycloak.common.util.KeycloakUriBuilder;
+import org.keycloak.common.util.MultivaluedHashMap;
import org.keycloak.common.util.UriUtils;
import org.keycloak.models.ClientModel;
import org.keycloak.models.Constants;
@@ -46,6 +49,22 @@
public static final Set<String> LOOPBACK_INTERFACES = new HashSet<>(Arrays.asList("localhost", "127.0.0.1", "[::1]"));
+ private static final Set<String> FORBIDDEN_OIDC_PARAMS = Set.of(
+ OAuth2Constants.CODE,
+ OAuth2Constants.ID_TOKEN,
+ OAuth2Constants.ACCESS_TOKEN,
+ OAuth2Constants.TOKEN_TYPE,
+ OAuth2Constants.EXPIRES_IN,
+ OAuth2Constants.STATE,
+ OAuth2Constants.ISSUER,
+ OAuth2Constants.ERROR,
+ OAuth2Constants.ERROR_DESCRIPTION,
+ OAuth2Constants.SESSION_STATE,
+ OAuth2Constants.RESPONSE,
+ Constants.KC_ACTION,
+ Constants.KC_ACTION_STATUS
+ );
+
private static final Logger logger = Logger.getLogger(RedirectUtils.class);
public static String verifyRedirectUri(KeycloakSession session, String redirectUri, ClientModel client) {
@@ -95,6 +114,11 @@
return null;
}
+ // Check for HTTP Parameter Pollution - forbidden OIDC response parameters in redirect URI
+ if (containsForbiddenOidcParameters(originalRedirect)){
+ return null;
+ }
+
// check if the passed URI allows wildcards
boolean allowWildcards = areWildcardsAllowed(originalRedirect);
@@ -135,6 +159,24 @@
}
}
+ private static boolean containsForbiddenOidcParameters(URI originalRedirect) {
+ String query = originalRedirect.getRawQuery();
+ if (query != null && !query.isEmpty()) {
+ MultivaluedHashMap<String, String> params =UriUtils.decodeQueryString(query);
+ for (String paramName : params.keySet()) {
+ if (FORBIDDEN_OIDC_PARAMS.contains(paramName.toLowerCase(Locale.ROOT))) {
+ logger.warnf("Redirect URI rejected: contains forbidden OIDC parameter '%s' in query string: scheme=%s, host=%s, path=%s",
+ paramName,
+ originalRedirect.getScheme(),
+ originalRedirect.getHost(),
+ originalRedirect.getPath());
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
private static URI toUri(String redirectUri) {
URI uri = null;
if (redirectUri != null) {
@@ -150,12 +192,16 @@
}
// any access to parent folder /../ is unsafe with or without encoding
+ // <sep> = / | %2F | %5C | \
+ // <dots> = "..", including %2E and %252E (double-encoded) variants
+ // <terminator> = / | %2F | %5C | \ | ; | %3B | %09 | %0A | %0D | %00 | end-of-input
private final static Pattern UNSAFE_PATH_PATTERN = Pattern.compile(
- "(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|\\.){2}(/|%2[fF]|%5[cC]|\\\\|;)|(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|\\.){2}$");
+ "(/|%2[fF]|%5[cC]|\\\\)(%2[eE]|%252[eE]|\\.){2}(/|%2[fF]|%5[cC]|\\\\|;|%3[bB]|%09|%0[aAdD]|%00|$)");
private static boolean areWildcardsAllowed(URI redirectUri) {
- // wildcars are only allowed if no user-info and no unsafe pattern in path
+ // wildcars are only allowed if no user-info and no unparsed authority and no unsafe pattern in path
return redirectUri.getRawUserInfo() == null
+ && !(redirectUri.getRawAuthority() != null && redirectUri.getRawUserInfo() == null && redirectUri.getHost() == null && redirectUri.getPort() == -1)
&& (redirectUri.getRawPath() == null || !UNSAFE_PATH_PATTERN.matcher(redirectUri.getRawPath()).find());
}
--
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