Description

Insertion of Sensitive Information Into Sent Data vulnerability in 10up ElasticPress allows Retrieve Embedded Sensitive Data. This issue affects ElasticPress: from n/a through 5.3.4.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.3",
  "pubDate": "2026-09-11T19:17:42.813Z",
  "pubdate": "2026-09-11T19:17:42.813Z",
  "executiveSummary": "The 10up ElasticPress plugin is susceptible to an Insertion of Sensitive Information Into Sent Data vulnerability, categorized under CWE-200. This security flaw enables unauthorized entities to retrieve sensitive data embedded within the synchronization or query process of the plugin.\nThe vulnerability affects all versions of ElasticPress from n/a through 5.3.4. The primary security impact involves the unauthorized disclosure of information that should otherwise remain restricted or protected within the WordPress environment.\nThe flaw allows an attacker to intercept or retrieve sensitive information that is transmitted or stored by the plugin during its normal operational lifecycle. This could lead to the exposure of configuration details, user metadata, or protected content, depending on what is being synchronized to the ElasticSearch instance.\nThe risk implication is significant as it potentially exposes internal application data to unauthorized parties who can access the data streams or the search index. Attackers do not necessarily need high-level administrative access if the underlying transport mechanism or the search index lacks adequate access control, allowing for information harvesting through targeted queries or interception of the data sent to the external search provider.",
  "technicalDetails": "The vulnerability originates from the insecure handling of sensitive data during the synchronization or transmission phase between the WordPress instance and the Elasticsearch server. ElasticPress functions by indexing WordPress content into Elasticsearch; during this serialization and transmission process, the plugin fails to adequately sanitize or filter data that may contain sensitive information before it is sent over the network.\nThe root cause is the inclusion of sensitive fields or metadata in the data structures passed to the indexing process. By failing to implement robust allow-lists or data-masking techniques, ElasticPress inadvertently embeds sensitive information into the searchable data set. This allows any entity capable of querying the Elasticsearch index or intercepting the synchronization traffic to extract data that the WordPress application intends to remain private.\nThe attack flow typically involves the following stages: 1) Identification of the synchronization trigger or API endpoint used by ElasticPress. 2) Interception or direct querying of the data stream being sent to the Elasticsearch backend. 3) Extraction of sensitive data that was improperly indexed. Because the plugin operates on the server-side, if the Elasticsearch instance is not configured with strictly scoped access control lists (ACLs) or encrypted transport protocols, an attacker can leverage the search interface to perform unrestricted queries, effectively dumping the sensitive information indexed by the plugin.\nThe vulnerability persists across all versions of ElasticPress from inception through version 5.3.4. It resides in the core indexing logic where the plugin prepares the document body for ElasticSearch storage. The flaw does not necessarily require complex exploit chains; if the communication between the WordPress server and the ElasticSearch cluster is over an unencrypted connection, it is susceptible to man-in-the-middle (MITM) attacks where the sensitive payloads can be harvested in transit.\nFurthermore, once the sensitive data is indexed in the Elasticsearch instance, the impact is compounded by the fact that the index acts as a permanent, searchable repository. Post-exploitation, an attacker gains unauthorized access to internal metadata, configuration settings, or PII (Personally Identifiable Information) that was inadvertently captured by the indexing process. The lack of granular egress filtering on the data being synchronized allows for the persistent leakage of backend information to the front-end search capabilities."
}