CVE-2025-52935: DragonflyDB Integer Overflow Vulnerability

CVE-2025-52935 Overview

CVE-2025-52935 is an Integer Overflow or Wraparound vulnerability affecting DragonflyDB's Dragonfly in-memory data store. The vulnerability exists within the Lua struct modules, specifically in the lua_struct.C program file, which handles data structure serialization and deserialization operations. When exploited, this integer overflow condition can lead to memory corruption, potentially enabling attackers to compromise the confidentiality, integrity, and availability of both the affected system and connected systems.

Critical Impact

This integer overflow vulnerability in DragonflyDB's Lua struct module can be exploited remotely with low privileges, potentially allowing attackers to corrupt memory and compromise data integrity across database operations.

Affected Products

• DragonflyDB Dragonfly version 1.30.1
• DragonflyDB Dragonfly version 1.30.0
• DragonflyDB Dragonfly version 1.28.18

Discovery Timeline

• 2025-06-23 - CVE-2025-52935 published to NVD
• 2025-06-23 - Last updated in NVD database

Technical Details for CVE-2025-52935

Vulnerability Analysis

The vulnerability resides in DragonflyDB's Lua struct module implementation within lua_struct.C. This module provides functionality for packing and unpacking binary data structures from Lua scripts, commonly used for serialization operations within the Redis-compatible database engine.

Integer overflow vulnerabilities in struct handling code typically occur when size calculations for data structures exceed the maximum value representable by the integer type, causing the value to wrap around to a much smaller number. In the context of lua_struct.C, this wraparound can result in undersized buffer allocations followed by out-of-bounds memory writes when the actual data is processed.

The network-accessible nature of this vulnerability combined with low privilege requirements makes it particularly dangerous for production DragonflyDB deployments, as authenticated users with minimal access could potentially trigger the overflow condition through crafted Lua script operations.

Root Cause

The root cause is classified as CWE-190 (Integer Overflow or Wraparound). The vulnerable code in lua_struct.C performs arithmetic operations on integer values related to structure size calculations without adequate bounds checking. When specially crafted input causes these calculations to overflow, the resulting value wraps around, leading to memory safety violations.

This type of vulnerability is common in C/C++ code handling variable-length data structures, where size parameters derived from user input are used in memory allocation and buffer operations without proper validation against integer overflow conditions.

Attack Vector

The vulnerability is exploitable over the network with low attack complexity. An attacker with low-level privileges (such as an authenticated database user) can craft malicious Lua struct operations that trigger the integer overflow condition.

The attack flow involves sending specially crafted Lua struct pack/unpack operations to the DragonflyDB instance that cause integer arithmetic to overflow during size calculations. When the overflow occurs, subsequent memory operations use the wrapped-around (smaller) value, leading to heap corruption or buffer overflows that can potentially be leveraged for further exploitation.

For technical details on the vulnerability and the specific fix implemented, refer to the GitHub Pull Request #4996 and the associated commit.

Detection Methods for CVE-2025-52935

Indicators of Compromise

• Unexpected DragonflyDB process crashes or segmentation faults during Lua script execution
• Abnormal memory consumption patterns in DragonflyDB instances
• Log entries indicating memory corruption or heap errors in the Dragonfly process
• Unusual Lua struct operations with extremely large size parameters in database logs

Detection Strategies

• Monitor DragonflyDB instances for unexpected process terminations or restarts that may indicate exploitation attempts
• Implement application-layer monitoring to detect anomalous Lua script execution patterns
• Deploy memory corruption detection tools (such as AddressSanitizer in non-production environments) to identify overflow conditions
• Review database access logs for suspicious struct pack/unpack operations with unusually large parameters

Monitoring Recommendations

• Enable comprehensive logging for Lua script operations in DragonflyDB deployments
• Configure alerting for DragonflyDB process crashes or unexpected restarts
• Monitor system memory metrics for anomalous allocation patterns associated with database operations
• Implement network monitoring to detect potential exploitation traffic targeting DragonflyDB ports

How to Mitigate CVE-2025-52935

Immediate Actions Required

• Upgrade affected DragonflyDB installations to a patched version immediately
• Restrict network access to DragonflyDB instances to only trusted clients and networks
• Review and audit Lua scripts executed against affected database instances
• Consider temporarily disabling Lua scripting capabilities if not required for operations

Patch Information

DragonflyDB has addressed this vulnerability through commit 473e002c848eb312f23d84114eb4951a7c4af5a1. The fix is documented in Pull Request #4996, which implements proper bounds checking for integer arithmetic operations in the Lua struct module.

Organizations should update to a patched version of DragonflyDB that incorporates this fix. Verify your installed version is not 1.30.1, 1.30.0, or 1.28.18, as these versions are confirmed vulnerable.

Workarounds

• Restrict network access to DragonflyDB instances using firewall rules to limit exposure to trusted networks only
• Disable or restrict Lua scripting functionality if not required for application operations
• Implement strict input validation at the application layer before data reaches DragonflyDB
• Deploy DragonflyDB behind a reverse proxy with request filtering capabilities to limit potentially malicious struct operations

# Example: Restrict DragonflyDB network access using iptables
# Allow connections only from trusted application servers
iptables -A INPUT -p tcp --dport 6379 -s 10.0.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 6379 -j DROP