Unable to apply field level security – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch fails to apply security restrictions on specific fields within an index. This could be due to incorrect configuration of field-level security settings or insufficient user permissions. To resolve this issue, you can check and correct the field-level security configuration in your Elasticsearch settings. Also, ensure that the user has the necessary permissions to access the fields. If the problem persists, consider reindexing your data or upgrading your Elasticsearch version, as some older versions may have bugs related to field-level security.

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

Log Context

Log “Unable to apply field level security” classname is SecurityIndexReaderWrapper.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


            return permissions.getFieldPermissions().filter(wrappedReader);
        } catch (IOException e) {
            logger.error("Unable to apply field level security");
            throw ExceptionsHelper.convertToElastic(e);

    protected IndicesAccessControl getIndicesAccessControl() {


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