Token malformed – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.6

Briefly, this error occurs when Elasticsearch encounters a malformed token during a query or data ingestion process. This could be due to incorrect syntax, invalid characters, or incorrect data types. To resolve this issue, you can: 1) Review the query or data causing the error and correct any syntax errors or invalid characters. 2) Ensure that the data types match the mapping defined in the index. 3) If the error is due to a token filter, check the configuration and adjust it as necessary.

This guide will help you check for common problems that cause the log ” token malformed ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Log Context

Log “token malformed” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 * is up to the client to re-authenticate and obtain a new token. The format for this response
 * is defined in  */
 private static ElasticsearchSecurityException malformedTokenException() {
 ElasticsearchSecurityException e =
 new ElasticsearchSecurityException("token malformed"; RestStatus.UNAUTHORIZED);
 e.addHeader("WWW-Authenticate"; MALFORMED_TOKEN_WWW_AUTH_VALUE);
 return e;
 }  /**


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