CVE-2026-24810: RethinkDB Buffer Overflow Vulnerability

CVE-2026-24810 Overview

CVE-2026-24810 is a critical Buffer Overflow vulnerability affecting RethinkDB, specifically within the src/cjson modules. The vulnerability exists in the cJSON.Cc program file, where buffer copy operations are performed without properly checking the size of input data. This classic buffer overflow condition can allow attackers to overwrite adjacent memory, potentially leading to arbitrary code execution, denial of service, or complete system compromise.

Critical Impact

This vulnerability has a maximum CVSS score, indicating that successful exploitation could result in complete compromise of confidentiality, integrity, and availability of both the vulnerable system and potentially connected systems.

Affected Products

• RethinkDB through v2.4.4
• Applications using RethinkDB's cJSON parsing modules
• Systems running vulnerable RethinkDB database instances

Discovery Timeline

• 2026-01-27 - CVE-2026-24810 published to NVD
• 2026-01-27 - Last updated in NVD database

Technical Details for CVE-2026-24810

Vulnerability Analysis

This vulnerability is classified as CWE-120 (Buffer Copy without Checking Size of Input), commonly known as a "Classic Buffer Overflow." The flaw resides within the cJSON parsing component of RethinkDB, which is responsible for handling JSON data structures. When processing specially crafted JSON input, the vulnerable code copies data into a fixed-size buffer without adequate bounds checking.

The vulnerability is exploitable over the network without requiring authentication or user interaction, making it particularly dangerous in environments where RethinkDB is exposed to untrusted networks. An attacker can craft malicious JSON payloads that, when processed by the vulnerable cJSON module, overflow the destination buffer and corrupt adjacent memory regions.

Root Cause

The root cause lies in the cJSON.Cc source file where input data is copied to a buffer without verifying that the source data length does not exceed the destination buffer's capacity. This is a fundamental memory safety issue that allows attackers to write data beyond the intended memory boundaries.

In classic buffer overflow scenarios like this, the vulnerable code likely uses unsafe string or memory copy functions (such as strcpy(), sprintf(), or memcpy()) without proper length validation. The cJSON library is responsible for parsing JSON text into C data structures, and any unchecked copy operation during this parsing process can be exploited.

Attack Vector

The attack vector for CVE-2026-24810 is network-based. An attacker can exploit this vulnerability by sending maliciously crafted JSON data to a RethinkDB instance. The attack does not require any special privileges or user interaction, making it highly exploitable in production environments.

The exploitation flow typically involves:

1. Identifying a RethinkDB instance accessible over the network
2. Crafting a JSON payload with oversized fields designed to overflow the target buffer
3. Sending the malicious payload to trigger the vulnerable code path in cJSON.Cc
4. Achieving memory corruption that can lead to code execution or system crash

The vulnerability manifests during JSON parsing operations in the cJSON module. Technical details regarding the specific overflow condition can be found in the GitHub Pull Request Discussion.

Detection Methods for CVE-2026-24810

Indicators of Compromise

• Unexpected crashes or segmentation faults in RethinkDB processes
• Anomalous JSON payloads with unusually long field values in network traffic to RethinkDB ports
• Memory corruption artifacts or core dumps from the RethinkDB service
• Unusual process behavior following JSON parsing operations

Detection Strategies

• Monitor RethinkDB logs for crash events or memory access violations related to JSON processing
• Implement network traffic analysis to detect oversized or malformed JSON payloads targeting RethinkDB
• Deploy memory protection mechanisms (ASLR, stack canaries) that can detect or prevent buffer overflow exploitation
• Use application-level firewalls to filter suspicious JSON input before it reaches RethinkDB

Monitoring Recommendations

• Enable verbose logging for RethinkDB to capture parsing errors and potential exploitation attempts
• Set up alerts for RethinkDB service crashes or unexpected restarts
• Monitor system resource usage for signs of denial-of-service conditions
• Implement network intrusion detection rules targeting known buffer overflow attack patterns

How to Mitigate CVE-2026-24810

Immediate Actions Required

• Restrict network access to RethinkDB instances to trusted hosts only
• Implement input validation and size limits on JSON data before it reaches RethinkDB
• Consider deploying a reverse proxy or application firewall to filter malicious payloads
• Monitor for patches from the RethinkDB project and plan for immediate deployment

Patch Information

Review the GitHub Pull Request Discussion for details on the fix and updated versions. Organizations should monitor the RethinkDB project for official releases that address this vulnerability and apply updates as soon as they become available.

Workarounds

• Isolate RethinkDB instances behind network firewalls and restrict access to trusted clients only
• Implement JSON payload size limits at the application or network layer to prevent oversized inputs
• Use network segmentation to limit the potential impact of a compromised database server
• Consider disabling or restricting features that process untrusted JSON input until patches are applied

# Example: Restrict RethinkDB access using iptables
# Allow only trusted IP addresses to connect to RethinkDB default port
iptables -A INPUT -p tcp --dport 28015 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 28015 -j DROP

# Enable connection logging for monitoring
iptables -A INPUT -p tcp --dport 28015 -j LOG --log-prefix "RethinkDB Access: "