CVE-2026-41081 Apache Storm Client: Anonymous principal assigned on TLS client certificate verification failure

What is CVE-2026-41081?

CVE-2026-41081 is a medium-severity authentication bypass vulnerability in Apache Storm Client, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

Weakness: CWE-287

Which versions are affected by CVE-2026-41081?

2 open source packages ship an affected version, including org.apache.storm:storm-client. It affects 1 product.

Products include Apache Storm.

How do I fix CVE-2026-41081?

Upgrade org.apache.storm:storm-client to 2.8.7 or later.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-41081 being exploited?

There is no known exploitation of CVE-2026-41081 in the wild and no public exploit code.

Other vulnerabilities in Apache Storm Client

• CVE-2021-38294 Shell Command Injection Vulnerability in Nimbus Thrift Server Critical 9.8
• CVE-2021-40865 Unsafe Pre-Authentication Deserialization In Workers Critical 9.8
• CVE-2018-11779 Deserialization of Untrusted Data in Apache Storm Critical 9.8
• CVE-2015-3188 Apache Storm remote code execution vulnerability Critical 9.8
• CVE-2026-35337 Apache Storm Client: RCE through Unsafe Deserialization via Kerberos TGT Credential Handling High 8.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-j2q8-xx3q-8fqh.