CVE-2025-49146: PostgreSQL JDBC Driver Auth Bypass Issue

CVE-2025-49146 Overview

CVE-2025-49146 is an authentication bypass vulnerability in pgjdbc, the open source PostgreSQL JDBC Driver. When the driver is configured with channel binding set to required (the default value is prefer), versions 42.7.4 through 42.7.6 incorrectly allow connections to proceed with authentication methods that do not support channel binding. This includes password, MD5, GSS, and SSPI authentication methods. The vulnerability could allow a man-in-the-middle attacker to intercept connections that users believed were protected by channel binding requirements.

Critical Impact

Man-in-the-middle attackers can bypass channel binding requirements and intercept database connections, potentially exposing sensitive authentication credentials and data.

Affected Products

• PostgreSQL JDBC Driver versions 42.7.4 to 42.7.6
• Applications using pgjdbc with channel binding set to required
• Java 8+ environments utilizing vulnerable driver versions

Discovery Timeline

• 2025-06-11 - CVE-2025-49146 published to NVD
• 2025-06-11 - PostgreSQL releases security patch version 42.7.7
• 2025-10-06 - Last updated in NVD database

Technical Details for CVE-2025-49146

Vulnerability Analysis

This vulnerability falls under CWE-287 (Improper Authentication). The core issue lies in the PostgreSQL JDBC driver's failure to properly enforce channel binding requirements during the authentication handshake. When a user explicitly configures the driver to require channel binding for enhanced security, the driver should reject any authentication method that cannot provide channel binding proof. However, the vulnerable versions incorrectly accept fallback authentication methods (password, MD5, GSS, SSPI) that lack channel binding support.

Channel binding is a security mechanism that cryptographically ties the authentication to the specific TLS session, preventing credential forwarding attacks. By accepting non-channel-binding authentication when required is specified, the driver undermines the security guarantee users expect from this configuration.

Root Cause

The root cause is a logic flaw in the authentication negotiation process. When the PostgreSQL server responds with an authentication method that does not support channel binding, the driver fails to validate this against the user's channelBinding=required configuration. Instead of rejecting the connection and raising an error, the driver proceeds with the insecure authentication method, creating a false sense of security for administrators who believed they had enforced channel binding.

Attack Vector

An attacker positioned to perform a man-in-the-middle attack on the network path between a JDBC client and PostgreSQL server can exploit this vulnerability. The attacker intercepts the TLS connection and manipulates the authentication handshake to force a downgrade to a non-channel-binding authentication method. Since the driver incorrectly accepts this fallback, the attacker can capture authentication credentials or maintain a position to intercept subsequent queries and data.

The attack requires network access to intercept traffic between the client and database server, making it exploitable in scenarios where network security is compromised or in untrusted network environments.

# Security patch in docs/data/versions.toml - Version update
 # Recent Versions
 [[recent]]
 j_name= "Java 8"
-version= "42.7.6"
+version= "42.7.7"
 suffix=""
 description= "If you are using Java 8 or newer then you should use the JDBC 4.2 version."
-url= "/download/postgresql-42.7.6.jar"
+url= "/download/postgresql-42.7.7.jar"
 
 [[recent]]
 j_name= "Java 7"

Source: GitHub Commit

Detection Methods for CVE-2025-49146

Indicators of Compromise

• Database connections completing successfully with MD5 or password authentication when channel binding is configured as required
• Unexpected authentication method negotiation in PostgreSQL server logs
• Network traffic analysis showing authentication handshakes without SCRAM-SHA-256-PLUS channel binding tokens
• Client applications not receiving expected channel binding enforcement errors

Detection Strategies

• Audit application dependencies to identify pgjdbc versions between 42.7.4 and 42.7.6
• Monitor PostgreSQL server logs for authentication method mismatches with expected channel binding requirements
• Implement network monitoring to detect potential man-in-the-middle positioning on database connection paths
• Review JDBC connection strings and configuration files for channelBinding=required settings paired with vulnerable driver versions

Monitoring Recommendations

• Enable detailed authentication logging on PostgreSQL servers to track authentication methods used per connection
• Implement dependency scanning in CI/CD pipelines to flag vulnerable pgjdbc versions
• Deploy network intrusion detection systems to monitor for TLS downgrade attempts on database ports
• Set up alerts for authentication anomalies or unexpected connection patterns

How to Mitigate CVE-2025-49146

Immediate Actions Required

• Upgrade pgjdbc to version 42.7.7 or later immediately
• Audit all Java applications and services using PostgreSQL JDBC connections
• Review Maven, Gradle, or other dependency management configurations for pgjdbc version references
• Verify channel binding is functioning correctly after upgrade by testing authentication behavior

Patch Information

The vulnerability is fixed in pgjdbc version 42.7.7, released on June 11, 2025. The fix ensures that when channelBinding=required is configured, the driver properly rejects authentication methods that do not support channel binding. Users should update their dependencies to this version or later. The security advisory and patch details are available via the GitHub Security Advisory.

Workarounds

• Temporarily configure channelBinding=prefer while understanding this provides opportunistic rather than mandatory channel binding
• Implement network-level security controls (VPNs, private networks) to reduce man-in-the-middle attack surface
• Enforce SCRAM-SHA-256-PLUS authentication at the PostgreSQL server level to prevent fallback to weaker methods
• Use mutual TLS authentication as an additional layer of client verification

# Maven dependency update example
# Update pom.xml to use patched version:
# <dependency>
#   <groupId>org.postgresql</groupId>
#   <artifactId>postgresql</artifactId>
#   <version>42.7.7</version>
# </dependency>

# Gradle dependency update:
# implementation 'org.postgresql:postgresql:42.7.7'