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TLS hostname verification is a critical security control that ensures a client is communicating with the intended server and not an impostor. During a TLS handshake, the server presents an X.509 certificate containing its identity—typically in the Subject Alternative Name (SAN) or Common Name (CN) field. The client is supposed to validate that this presented hostname matches the hostname it originally requested. CVE-2026-65942 exists because the Apache Ranger Client Code, in versions up to and including 2.8.0, fails to perform this essential check.
The vulnerability resides in the client-side TLS validation routine used by Apache Ranger plugins and client applications when establishing secure connections to Ranger servers, including the Ranger Admin Server and Policy Management services. When a TLS client does not validate the certificate’s hostname, it becomes susceptible to accepting certificates issued for entirely different hosts. An attacker positioned as a man-in-the-middle (MITM) can present a valid certificate for any domain they control—or leverage a mis-issued certificate—and successfully impersonate the legitimate Ranger server. The TLS handshake completes successfully because the certificate chain is trusted by the client’s trust store, but the client never checks that the certificate’s identity matches the server it intended to reach.
This flaw affects all network paths where a Ranger client establishes TLS connections: the plugin-to-server communication channel used by HDFS, Hive, HBase, and other Hadoop ecosystem components to fetch policies; the Ranger Admin UI client-to-server connections; and any third-party integrations that programmatically connect to the Ranger REST API. Because the vulnerability is in the client code, every deployment relying on these secured communications is potentially exposed. The issue was discovered by Andrew Rukin of Arenadata and reported to the Apache Security Team. Apache has released version 2.9.0, which addresses the flaw by introducing proper hostname verification in the client’s SSL/TLS validation routine.
DailyCVE Form:
Platform: Apache Ranger
Version: <= 2.8.0
Vulnerability: TLS hostname validation
Severity: Moderate
date: 2026-08-10
Prediction: Patch expected 2026-08-10
What Undercode Say:
Check Apache Ranger version ranger-admin -version Verify current version from build.properties cat /usr/lib/ranger/hadoop/ranger-.jar/META-INF/MANIFEST.MF | grep "Implementation-Version" Search for TLS hostname verification settings in configuration grep -r "ssl.hostname.verification" /etc/ranger/conf/ grep -r "hostname.verification" /etc/ranger/conf/ Check if hostname verification is disabled grep "ranger.plugin.ssl.hostname.verification" /etc/ranger//ranger-.xml Example vulnerable configuration (hostname verification disabled) <property> <name>ranger.plugin.hdfs.ssl.hostname.verification</name> <value>false</value> </property> Test TLS connection without hostname verification (using openssl) openssl s_client -connect ranger.example.com:443 -servername ranger.example.com -verify_return_error 2>&1 | grep "Verify return code" Check if certificate SAN matches expected hostname openssl s_client -connect ranger.example.com:443 -servername ranger.example.com 2>&1 | openssl x509 -noout -text | grep -A1 "Subject Alternative Name"
Exploit: (Educational Purposes!)
Attacker sets up MITM position (ARP spoofing or DNS poisoning)
Attacker obtains a valid TLS certificate for attacker.com
Attacker intercepts Ranger client connection
Present certificate for attacker.com instead of ranger.example.com
Vulnerable Ranger client accepts the certificate without hostname verification
Example: Using mitmproxy to demonstrate the flaw
mitmproxy --mode transparent --showhost -s intercept_ranger.py
Python script to simulate vulnerable client behavior
import ssl
import socket
context = ssl.create_default_context()
Hostname verification is disabled (vulnerable behavior)
context.check_hostname = False
Certificate chain is still validated
context.verify_mode = ssl.CERT_REQUIRED
with socket.create_connection(("ranger.example.com", 443)) as sock:
with context.wrap_socket(sock) as ssock:
Certificate for attacker.com is accepted
print(ssock.getpeercert())
Protection:
Upgrade to Apache Ranger version 2.9.0 immediately. If immediate upgrade is not possible, ensure hostname verification is explicitly enabled in all Ranger client configurations by setting `ranger.plugin..ssl.hostname.verification` to `true` (default behavior in patched versions). Review all Ranger plugin configurations for HDFS, Hive, HBase, and other components to confirm hostname verification is not disabled. Monitor Ranger client logs for TLS handshake errors that may indicate attempted MITM attacks. Implement network-level controls to prevent unauthorized access to Ranger server endpoints and use certificate pinning where feasible.
Impact:
Successful exploitation allows an attacker to intercept, decrypt, and potentially modify all TLS-encrypted traffic between Ranger clients and Ranger servers. This includes policy data fetched by Hadoop ecosystem components, administrative credentials, API tokens, and sensitive configuration information transmitted over the wire. The attacker can impersonate the Ranger Admin Server, potentially leading to unauthorized policy changes, privilege escalation, and complete compromise of the Ranger-managed authorization framework. Organizations running Apache Ranger version 2.8.0 or earlier in production environments face elevated risk of data interception and credential theft across their Hadoop and big data infrastructure.
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Sources:
Reported By: nvd.nist.gov
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