CVE-2026-25208: Samsung Escargot Buffer Overflow Flaw

CVE-2026-25208 Overview

An integer overflow vulnerability exists in Samsung's Open Source Escargot JavaScript engine that can lead to buffer overflow conditions. This memory corruption issue affects the Escargot project at commit 97e8115ab1110bc502b4b5e4a0c689a71520d335. The vulnerability occurs when integer values exceed their maximum bounds during calculations, potentially causing unexpected behavior that could be leveraged by attackers to overflow memory buffers.

Critical Impact

This integer overflow vulnerability could allow remote attackers to trigger buffer overflows, potentially leading to arbitrary code execution, information disclosure, or denial of service conditions in applications using the affected Escargot JavaScript engine.

Affected Products

• Samsung Open Source Escargot (commit 97e8115ab1110bc502b4b5e4a0c689a71520d335)
• Applications and embedded systems utilizing the affected Escargot JavaScript engine version

Discovery Timeline

• 2026-04-13 - CVE-2026-25208 published to NVD
• 2026-04-13 - Last updated in NVD database

Technical Details for CVE-2026-25208

Vulnerability Analysis

This vulnerability is classified as CWE-190 (Integer Overflow or Wraparound), a memory corruption flaw that occurs when arithmetic operations produce values that exceed the storage capacity of the integer type being used. In the context of the Escargot JavaScript engine, this integer overflow can subsequently lead to buffer overflow conditions.

When an integer variable is incremented or manipulated beyond its maximum value, it wraps around to a minimum value or produces an unexpected result. If this incorrect value is then used for memory allocation sizes, array bounds, or loop counters, it can result in undersized buffer allocations or out-of-bounds memory access. The network-based attack vector indicates that this vulnerability could potentially be triggered by processing maliciously crafted JavaScript code or input data.

Root Cause

The root cause of CVE-2026-25208 stems from insufficient validation of integer arithmetic operations within the Escargot JavaScript engine. When performing calculations that determine buffer sizes or array indices, the code fails to properly check for integer overflow conditions before using the computed values. This allows attackers to supply input that causes integer wraparound, resulting in smaller-than-expected memory allocations that are subsequently overflowed when data is written to them.

Attack Vector

The vulnerability is exploitable via network-based attack vectors. An attacker could potentially craft malicious JavaScript code or input that triggers the integer overflow condition when processed by the Escargot engine. The attack does not require authentication or user interaction, though exploitation complexity is considered high due to the specific conditions required to successfully leverage the overflow for malicious purposes.

The attack flow involves:

1. Attacker crafts input designed to trigger arithmetic operations that overflow integer bounds
2. The overflowed value is used for buffer allocation, resulting in an undersized buffer
3. Subsequent operations write data exceeding the allocated buffer size
4. This overflow can corrupt adjacent memory, potentially allowing code execution or information disclosure

For technical details on the vulnerability and associated fixes, see the GitHub Pull Request Discussion.

Detection Methods for CVE-2026-25208

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications using the Escargot JavaScript engine
• Memory corruption errors or heap corruption warnings in system logs
• Abnormal memory usage patterns in processes running Escargot-based applications
• Unusual JavaScript execution errors that may indicate exploitation attempts

Detection Strategies

• Monitor for crash dumps containing Escargot-related stack traces that indicate integer overflow or buffer overflow conditions
• Implement runtime memory protection mechanisms such as ASLR and stack canaries to detect exploitation attempts
• Deploy application-level logging to identify malformed or unusually large numeric inputs being processed
• Use static analysis tools to scan codebases for usage of the vulnerable Escargot commit

Monitoring Recommendations

• Enable verbose logging in applications using the Escargot engine to capture potential exploitation attempts
• Implement memory monitoring and alerting for applications running vulnerable versions
• Monitor network traffic for suspicious JavaScript payloads targeting embedded systems or IoT devices using Escargot
• Set up automated vulnerability scanning to detect presence of the vulnerable Escargot version in your environment

How to Mitigate CVE-2026-25208

Immediate Actions Required

• Identify all applications and systems utilizing the Samsung Escargot JavaScript engine
• Update Escargot to a version that includes the fix for this integer overflow vulnerability
• If immediate patching is not possible, consider temporarily disabling or isolating affected applications
• Review the GitHub Pull Request for specific patch details and guidance

Patch Information

Samsung has addressed this vulnerability through pull request #1554 in the Escargot repository. Organizations using Escargot should update to a commit that includes this fix or a subsequent release that incorporates the security patch. The patch addresses the integer overflow condition by implementing proper bounds checking for arithmetic operations that could lead to buffer overflows.

Workarounds

• Implement input validation at the application layer to restrict numeric inputs to safe ranges before processing with Escargot
• Deploy additional memory protection mechanisms such as Address Sanitizer (ASan) in development environments to detect overflow conditions
• Consider sandboxing applications that use the Escargot engine to limit the impact of potential exploitation
• Monitor and restrict network access to systems running vulnerable Escargot versions until patching is complete

# Example: Building Escargot with Address Sanitizer for testing
git clone https://github.com/Samsung/escargot.git
cd escargot
git checkout main  # Ensure you're on the latest patched version
cmake -DCMAKE_BUILD_TYPE=Debug -DENABLE_ASAN=ON .
make