Apache Storm Client: Anonymous principal assigned on TLS client certificate verification failure

Summary

Improper Handling of TLS Client Authentication Failure Leading to Anonymous Principal Assignment in Apache Storm Versions Affected: up to 2.8.7 Description: When TLS transport is enabled in Apache Storm without requiring client certificate authentication (the default configuration), the TlsTransportPlugin assigns a fallback principal (CN=ANONYMOUS) if no client certificate is presented or if certificate verification fails. The underlying SSLPeerUnverifiedException is caught and suppressed rather than rejecting the connection. This fail-open behavior means an unauthenticated client can establish a TLS connection and receive a valid principal identity. If the configured authorizer (e.g., SimpleACLAuthorizer) does not explicitly deny access to CN=ANONYMOUS, this may result in unauthorized access to Storm services. The condition is logged at debug level only, reducing visibility in production. Impact: Unauthenticated clients may be assigned a principal identity, potentially bypassing authorization in permissive or misconfigured environments. Mitigation: Users should upgrade to 2.8.7 in which TLS authentication failures are handled in a fail-closed manner. Users who cannot upgrade immediately should: • Enable mandatory client certificate authentication (nimbus.thrift.tls.client.auth.required: true) • Ensure authorization rules explicitly deny access to CN=ANONYMOUS • Review all ACL configurations for implicit default-allow behavior

Timeline

1. Apr 27, 2026, 1:10 PM UTCCVE published
2. Apr 27, 2026, 2:42 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Apr 27, 2026, 2:43 PM UTCRecord last updated

Affected versions

• org.apache.storm:storm-client

  fixed in 2.8.7

• org.apache.storm:storm-clientMaven

  fixed in 2.8.7

References 1