TLS hostname verification cannot be enabled in the Pulsar Broker's Java Client, the Pulsar Broker's Java Admin Client, the Pulsar WebSocket Proxy's Java Client, and the Pulsar Proxy's Admin Client leaving intra-cluster connections and geo-replication connections vulnerable to man in the middle attacks, which could leak credentials, configuration data, message data, and any other data sent by these clients. The vulnerability is for both the pulsar+ssl protocol and HTTPS. An attacker can only take advantage of this vulnerability by taking control of a machine 'between' the client and the server. The attacker must then actively manipulate traffic to perform the attack by providing the client with a cryptographically valid certificate for an unrelated host. This issue affects Apache Pulsar Broker, Proxy, and WebSocket Proxy versions 2.7.0 to 2.7.4; 2.8.0 to 2.8.3; 2.9.0 to 2.9.2; 2.10.0; 2.6.4 and earlier.

A flaw was found in the Apache Pulsar Java Client. This flaw allows an attacker to use a Man-in-the-Middle (MITM) attack, manipulating network traffic and gaining the client's authentication data.

Improper Input Validation vulnerability in Proxy component of Apache Pulsar allows an attacker to make TCP/IP connection attempts that originate from the Pulsar Proxy's IP address. When the Apache Pulsar Proxy component is used, it is possible to attempt to open TCP/IP connections to any IP address and port that the Pulsar Proxy can connect to. An attacker could use this as a way for DoS attacks that originate from the Pulsar Proxy's IP address. It hasn’t been detected that the Pulsar Proxy authentication can be bypassed. The attacker will have to have a valid token to a properly secured Pulsar Proxy. This issue affects Apache Pulsar Proxy versions 2.7.0 to 2.7.4; 2.8.0 to 2.8.2; 2.9.0 to 2.9.1; 2.6.4 and earlier.

Apache Pulsar Brokers and Proxies create an internal Pulsar Admin Client that does not verify peer TLS certificates, even when tlsAllowInsecureConnection is disabled via configuration. The Pulsar Admin Client's intra-cluster and geo-replication HTTPS connections are vulnerable to man in the middle attacks, which could leak authentication data, configuration data, and any other data sent by these clients. An attacker can only take advantage of this vulnerability by taking control of a machine 'between' the client and the server. The attacker must then actively manipulate traffic to perform the attack. This issue affects Apache Pulsar Broker and Proxy versions 2.7.0 to 2.7.4; 2.8.0 to 2.8.3; 2.9.0 to 2.9.2; 2.10.0; 2.6.4 and earlier.

The Apache Pulsar C++ Client does not verify peer TLS certificates when making HTTPS calls for the OAuth2.0 Client Credential Flow, even when tlsAllowInsecureConnection is disabled via configuration. This vulnerability allows an attacker to perform a man in the middle attack and intercept and/or modify the GET request that is sent to the ClientCredentialFlow 'issuer url'. The intercepted credentials can be used to acquire authentication data from the OAuth2.0 server to then authenticate with an Apache Pulsar cluster. An attacker can only take advantage of this vulnerability by taking control of a machine 'between' the client and the server. The attacker must then actively manipulate traffic to perform the attack. The Apache Pulsar Python Client wraps the C++ client, so it is also vulnerable in the same way. This issue affects Apache Pulsar C++ Client and Python Client versions 2.7.0 to 2.7.4; 2.8.0 to 2.8.3; 2.9.0 to 2.9.2; 2.10.0 to 2.10.1; 2.6.4 and earlier. Any users running affected versions of the C++ Client or the Python Client should rotate vulnerable OAuth2.0 credentials, including clientid and clientsecret. 2.7 C++ and Python Client users should upgrade to 2.7.5 and rotate vulnerable OAuth2.0 credentials. 2.8 C++ and Python Client users should upgrade to 2.8.4 and rotate vulnerable OAuth2.0 credentials. 2.9 C++ and Python Client users should upgrade to 2.9.3 and rotate vulnerable OAuth2.0 credentials. 2.10 C++ and Python Client users should upgrade to 2.10.2 and rotate vulnerable OAuth2.0 credentials. 3.0 C++ users are unaffected and 3.0 Python Client users will be unaffected when it is released. Any users running the C++ and Python Client for 2.6 or less should upgrade to one of the above patched versions.

Incorrect Authorization vulnerability in Apache Software Foundation Apache Pulsar Broker's Rest Producer allows authenticated user with a custom HTTP header to produce a message to any topic using the broker's admin role. This issue affects Apache Pulsar Brokers: from 2.9.0 through 2.9.5, from 2.10.0 before 2.10.4, 2.11.0.

The vulnerability is exploitable when an attacker can connect directly to the Pulsar Broker. If an attacker is connecting through the Pulsar Proxy, there is no known way to exploit this authorization vulnerability.

There are two known risks for affected users. First, an attacker could produce garbage messages to any topic in the cluster. Second, an attacker could produce messages to the topic level policies topic for other tenants and influence topic settings that could lead to exfiltration and/or deletion of messages for other tenants.

2.8 Pulsar Broker users and earlier are unaffected. 2.9 Pulsar Broker users should upgrade to one of the patched versions. 2.10 Pulsar Broker users should upgrade to at least 2.10.4. 2.11 Pulsar Broker users should upgrade to at least 2.11.1. 3.0 Pulsar Broker users are unaffected.