diff --git a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManager.java b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManager.java
index b246fb939b..f25933cf9c 100644
--- a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManager.java
+++ b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManager.java
@@ -40,10 +40,13 @@ import org.springframework.util.Assert;
  * @since 5.1
  */
 public final class JwtReactiveAuthenticationManager implements ReactiveAuthenticationManager {
+	private final ReactiveJwtDecoder jwtDecoder;
+
 	private Converter<Jwt, ? extends Mono<? extends AbstractAuthenticationToken>> jwtAuthenticationConverter
 			= new ReactiveJwtAuthenticationConverterAdapter(new JwtAuthenticationConverter());
 
-	private final ReactiveJwtDecoder jwtDecoder;
+	private static final OAuth2Error DEFAULT_INVALID_TOKEN =
+			invalidToken("An error occurred while attempting to decode the Jwt: Invalid token");
 
 	public JwtReactiveAuthenticationManager(ReactiveJwtDecoder jwtDecoder) {
 		Assert.notNull(jwtDecoder, "jwtDecoder cannot be null");
@@ -80,10 +83,15 @@ public final class JwtReactiveAuthenticationManager implements ReactiveAuthentic
 	}
 
 	private static OAuth2Error invalidToken(String message) {
-		return new BearerTokenError(
-				BearerTokenErrorCodes.INVALID_TOKEN,
-				HttpStatus.UNAUTHORIZED,
-				message,
-				"https://tools.ietf.org/html/rfc6750#section-3.1");
+		try {
+			return new BearerTokenError(
+					BearerTokenErrorCodes.INVALID_TOKEN,
+					HttpStatus.UNAUTHORIZED,
+					message,
+					"https://tools.ietf.org/html/rfc6750#section-3.1");
+		} catch (IllegalArgumentException malformed) {
+			// some third-party library error messages are not suitable for RFC 6750's error message charset
+			return DEFAULT_INVALID_TOKEN;
+		}
 	}
 }
diff --git a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManagerTests.java b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManagerTests.java
index 2e52bd69cb..536f76cfec 100644
--- a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManagerTests.java
+++ b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/authentication/JwtReactiveAuthenticationManagerTests.java
@@ -88,6 +88,19 @@ public class JwtReactiveAuthenticationManagerTests {
 				.isInstanceOf(OAuth2AuthenticationException.class);
 	}
 
+	// gh-7549
+	@Test
+	public void authenticateWhenDecoderThrowsIncompatibleErrorMessageThenWrapsWithGenericOne() {
+		BearerTokenAuthenticationToken token = new BearerTokenAuthenticationToken("token-1");
+		when(this.jwtDecoder.decode(token.getToken())).thenThrow(new JwtException("with \"invalid\" chars"));
+
+		assertThatCode(() -> this.manager.authenticate(token).block())
+				.isInstanceOf(OAuth2AuthenticationException.class)
+				.hasFieldOrPropertyWithValue(
+						"error.description",
+						"An error occurred while attempting to decode the Jwt: Invalid token");
+	}
+
 	@Test
 	public void authenticateWhenNotJwtExceptionThenPropagates() {
 		BearerTokenAuthenticationToken token = new BearerTokenAuthenticationToken("token-1");