CVE-2024-27304: Pgproto3 SQL Injection Vulnerability

CVE-2024-27304 Overview

CVE-2024-27304 is a critical SQL injection vulnerability affecting pgx, a popular PostgreSQL driver and toolkit for Go. The vulnerability stems from an integer overflow condition that occurs when processing messages exceeding 4 GB in size. When an attacker can cause a single query or bind message to exceed this threshold, an integer overflow in the calculated message size allows one large message to be sent as multiple messages under the attacker's control, enabling SQL injection attacks.

Critical Impact

This vulnerability allows remote attackers to perform SQL injection attacks without authentication, potentially leading to complete database compromise, data exfiltration, and unauthorized data manipulation.

Affected Products

• pgx PostgreSQL Driver for Go (versions prior to v4.18.2 and v5.5.4)
• pgproto3 PostgreSQL Protocol Library for Go
• Applications using vulnerable versions of pgx or pgproto3 for PostgreSQL connectivity

Discovery Timeline

• 2024-03-06 - CVE-2024-27304 published to NVD
• 2025-12-04 - Last updated in NVD database

Technical Details for CVE-2024-27304

Vulnerability Analysis

This vulnerability exploits a fundamental flaw in how pgx handles message size calculations. When processing PostgreSQL protocol messages, the library uses integer arithmetic to calculate the total message size. When this calculation involves data that causes the result to exceed the maximum value representable by the integer type (approximately 4 GB), an integer overflow occurs. This overflow causes the size value to wrap around, resulting in a much smaller calculated size than the actual data being processed.

The consequence of this overflow is particularly severe because it allows an attacker to manipulate how the PostgreSQL protocol messages are segmented. Instead of the library recognizing and handling a single large message appropriately, the overflowed size calculation causes the data to be split and interpreted as multiple separate messages. An attacker who can control portions of this data can craft malicious SQL commands that execute within the context of these artificially separated messages.

Root Cause

The root cause is an integer overflow vulnerability (CWE-89: SQL Injection) in the message size calculation logic within the pgx and pgproto3 libraries. The code responsible for computing message sizes does not properly validate or handle cases where the total size exceeds the 4 GB boundary, allowing arithmetic overflow to corrupt the size value and subsequently enable SQL injection through message fragmentation.

Attack Vector

The attack requires an adversary to be able to supply input data to a pgx-based application that results in a query or bind message exceeding 4 GB in total size. This is a network-based attack vector that does not require authentication or user interaction. Once the attacker can trigger the integer overflow condition, they gain control over how subsequent protocol messages are interpreted by the PostgreSQL server.

The attack flow involves:

1. The attacker identifies an application using a vulnerable version of pgx
2. Large input data is crafted to cause a query or bind message to exceed 4 GB
3. The integer overflow causes the message to be fragmented
4. Attacker-controlled SQL commands within the fragmented messages execute on the database

The vulnerability mechanism centers on the integer overflow in message size calculation. When the calculated message size exceeds approximately 4 billion bytes, the value wraps around due to integer overflow. This causes the pgx library to incorrectly determine message boundaries, allowing attacker-controlled data to be interpreted as separate SQL statements. For detailed technical analysis, refer to the pgx Security Advisory and the pgproto3 Security Advisory.

Detection Methods for CVE-2024-27304

Indicators of Compromise

• Unusually large database queries or bind operations exceeding several gigabytes in size
• Unexpected SQL execution patterns in PostgreSQL logs that don't match application behavior
• Database connection anomalies where single operations appear as multiple fragmented commands
• Evidence of data exfiltration or unauthorized database modifications following large query operations

Detection Strategies

• Monitor PostgreSQL server logs for unusually large queries or abnormal query patterns that may indicate exploitation attempts
• Implement application-level logging to track the size of data being passed to database operations
• Use network monitoring to detect abnormally large PostgreSQL protocol messages (approaching or exceeding 4 GB)
• Deploy database activity monitoring solutions to identify SQL injection patterns following legitimate query operations

Monitoring Recommendations

• Configure alerts for database queries with input parameters exceeding configurable size thresholds
• Enable PostgreSQL statement logging to capture all executed SQL for forensic analysis
• Implement network traffic analysis on database connections to identify oversized protocol messages
• Review application logs regularly for errors related to message size handling or database connectivity issues

How to Mitigate CVE-2024-27304

Immediate Actions Required

• Upgrade pgx to version v4.18.2 or v5.5.4 immediately to resolve the vulnerability
• Audit all Go applications for pgx and pgproto3 dependencies and schedule updates
• Implement input validation to reject user input large enough to cause single queries or bind messages to exceed 4 GB
• Review database access logs for any signs of exploitation prior to patching

Patch Information

The vulnerability has been resolved in pgx versions v4.18.2 and v5.5.4. The patches address the integer overflow condition by implementing proper size validation and bounds checking before message size calculations. Security patches are available through the following commits:

• pgproto3 patch commit
• pgx patch commit (v4 branch)
• pgx patch commit (v5 branch)
• pgx additional fix

Workarounds

• Implement application-level validation to reject any user input that could cause a single query or bind message to exceed 4 GB in size
• Configure web application firewalls or API gateways to limit request body sizes to prevent oversized payloads from reaching vulnerable applications
• Use database connection proxies that can inspect and limit PostgreSQL protocol message sizes
• Consider implementing query parameterization limits and data chunking for operations that handle large datasets

# Go module update commands for remediation
# Update pgx to patched version (v5.x)
go get github.com/jackc/pgx/v5@v5.5.4

# Update pgx to patched version (v4.x)
go get github.com/jackc/pgx/v4@v4.18.2

# Verify the updated version
go list -m github.com/jackc/pgx/v5
go list -m github.com/jackc/pgx/v4