CVE-2025-3277: SQLite Buffer Overflow Vulnerability

CVE-2025-3277 Overview

An integer overflow vulnerability exists in SQLite's concat_ws() function that can lead to a massive heap buffer overflow. When triggered, the integer overflow results in a truncated size value being used for buffer allocation. SQLite then writes the resulting string using the original, untruncated size, causing a heap buffer overflow of approximately 4GB. This vulnerability can result in arbitrary code execution on affected systems.

Critical Impact

This integer overflow vulnerability in SQLite's concat_ws() function can trigger a ~4GB heap buffer overflow, potentially enabling arbitrary code execution on systems running vulnerable versions of SQLite.

Affected Products

• SQLite (all vulnerable versions)
• Applications embedding SQLite database engine
• Systems and services utilizing SQLite for data storage

Discovery Timeline

• 2025-04-14 - CVE-2025-3277 published to NVD
• 2025-08-18 - Last updated in NVD database

Technical Details for CVE-2025-3277

Vulnerability Analysis

This vulnerability combines two dangerous memory corruption patterns: Integer Overflow (CWE-190) and Heap Buffer Overflow (CWE-122). The concat_ws() function in SQLite is designed to concatenate multiple string arguments using a specified separator. However, the function fails to properly validate the calculated size of the concatenated result before allocating memory for the output buffer.

When extremely large input strings are provided, the size calculation overflows, wrapping around to a small value due to integer truncation. SQLite then allocates a buffer based on this incorrectly small value. The subsequent write operation uses the original, untruncated size calculation, causing SQLite to write far beyond the bounds of the allocated buffer—potentially up to 4GB of data into heap memory that doesn't belong to the allocated object.

Root Cause

The root cause lies in insufficient bounds checking during the size calculation for buffer allocation in the concat_ws() function. The function computes the total length of the concatenated string result but fails to detect when this calculation exceeds the maximum value representable by the integer type used for the size. This integer overflow causes the allocated buffer to be significantly smaller than required, while the write operation proceeds with the true, larger size value.

Attack Vector

This vulnerability is exploitable over a network in scenarios where an attacker can influence the arguments passed to the concat_ws() function. Applications that accept user-controlled input and pass it to SQLite queries using concat_ws() are at risk. An attacker would craft malicious input strings designed to trigger the integer overflow condition, resulting in a heap buffer overflow that could be leveraged for arbitrary code execution.

The exploitation path involves:

1. Providing specially crafted large string arguments to concat_ws()
2. Triggering the integer overflow during size calculation
3. Causing allocation of an undersized buffer
4. Overwriting heap memory with attacker-controlled data
5. Potentially gaining code execution through heap corruption techniques

Detection Methods for CVE-2025-3277

Indicators of Compromise

• Unexpected application crashes or segmentation faults in SQLite-based applications
• Anomalous memory allocation patterns or heap corruption errors
• Unusually large string inputs being processed through database operations
• Evidence of heap spraying or memory manipulation techniques in application logs

Detection Strategies

• Monitor SQLite-based applications for abnormal memory usage or allocation failures
• Implement application-level logging for concat_ws() function calls with unusually large parameters
• Deploy runtime memory protection tools to detect heap buffer overflows
• Use address sanitizers (ASAN) during development and testing to catch memory corruption early

Monitoring Recommendations

• Enable heap integrity checking in production environments where feasible
• Configure crash dump collection and analysis for SQLite-dependent services
• Monitor for repeated application restarts that may indicate exploitation attempts
• Implement input size validation at the application layer before data reaches SQLite

How to Mitigate CVE-2025-3277

Immediate Actions Required

• Upgrade SQLite to the latest patched version immediately
• Review applications that use concat_ws() with user-controlled input
• Implement input validation to limit string sizes before they reach SQLite functions
• Consider temporarily disabling or restricting access to affected functionality if patching is not immediately possible

Patch Information

SQLite has released a security update addressing this vulnerability. The patch information is available in the SQLite Security Update. Organizations should update to the latest SQLite version that includes the fix for this integer overflow vulnerability.

Workarounds

• Implement application-level input validation to reject excessively large strings before they reach concat_ws()
• Use prepared statements with size limits on bound parameters
• Deploy Web Application Firewalls (WAF) to filter abnormally large input payloads
• Consider sandboxing SQLite operations to limit the impact of potential exploitation