GHSA-x5hg-x4gv-j98m OpenSearch has ineffective TLS certificate hostname verification
OpenSearch fails to verify TLS hostnames, allowing malicious nodes with valid CA-signed certificates to join clusters and access data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is GHSA-x5hg-x4gv-j98m?
GHSA-x5hg-x4gv-j98m is a vulnerability in org.opensearch.plugin:opensearch-security, published on 7 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Description
A regression was introduced in OpenSearch 2.18.0 that caused the plugins.security.ssl.transport.enforce_hostname_verification setting to be ineffective. When this setting was enabled, OpenSearch did not verify that the hostname in a connecting node's TLS certificate matched the hostname of the connection. This could allow a node with a valid certificate (signed by the cluster's trusted CA) but an incorrect hostname SAN to join the cluster.
Impact
Clusters running affected versions with hostname verification enabled did not receive the expected protection from this setting. A node presenting a certificate signed by the cluster's trusted CA could join the cluster regardless of whether its hostname SAN matched. This regression does not affect certificate validation itself — only the additional hostname verification check.
Patches
This issue is fixed in OpenSearch 2.19.4 and 3.3.0.
Workarounds
Use more restrictive values for plugins.security.nodes_dn to limit which certificates are accepted for node-to-node communication.
Which versions are affected by GHSA-x5hg-x4gv-j98m?
4 open source packages ship an affected version, including org.opensearch.plugin:opensearch-security.
| Package | Affected | Fixed in |
|---|---|---|
org.opensearch.plugin:opensearch-security Maven | From 2.18.0 | 2.19.4.0 |
org.opensearch.plugin:opensearch-security Maven | From 2.18.0 | 2.19.4.0 |
org.opensearch.plugin:opensearch-security Maven | From 3.0.0 | 3.3.0.0 |
org.opensearch.plugin:opensearch-security Maven | From 3.0.0 | 3.3.0.0 |
How do I fix GHSA-x5hg-x4gv-j98m?
Upgrade org.opensearch.plugin:opensearch-security to a fixed version for your release line: 2.19.4.0 or 3.3.0.0.
Is GHSA-x5hg-x4gv-j98m being exploited?
There is no known exploitation of GHSA-x5hg-x4gv-j98m in the wild and no public exploit code.