CVE-2026-25207: Samsung Escargot Buffer Overflow Flaw

CVE-2026-25207 Overview

CVE-2026-25207 is an out-of-bounds write vulnerability discovered in Samsung's open-source Escargot JavaScript engine. This memory corruption flaw enables attackers to write data beyond the boundaries of an allocated buffer, potentially leading to arbitrary code execution, application crashes, or system compromise. Escargot is a lightweight JavaScript engine designed for resource-constrained devices, making this vulnerability particularly concerning for embedded systems and IoT deployments.

Critical Impact

Successful exploitation of this out-of-bounds write vulnerability could allow attackers to execute arbitrary code with the privileges of the affected application, potentially gaining full control over vulnerable systems running the Escargot JavaScript engine.

Affected Products

• Samsung Escargot JavaScript Engine (commit 97e8115ab1110bc502b4b5e4a0c689a71520d335)
• Systems and applications utilizing the affected Escargot commit
• Embedded devices and IoT platforms running vulnerable Escargot versions

Discovery Timeline

• April 13, 2026 - CVE-2026-25207 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2026-25207

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption issue that occurs when the Escargot JavaScript engine writes data past the end or before the beginning of an allocated memory buffer. The local attack vector indicates that exploitation requires the attacker to have some level of local access or the ability to execute code locally, though no user interaction is required for successful exploitation.

The high complexity rating suggests that specific conditions must be met for successful exploitation, potentially involving precise memory layout manipulation or timing requirements. Despite this complexity barrier, the potential impact is severe, with confidentiality, integrity, and availability all at high risk of compromise.

Root Cause

The root cause stems from improper boundary checking within the Escargot JavaScript engine's memory handling routines. When processing certain JavaScript operations, the engine fails to properly validate buffer boundaries before performing write operations, allowing data to be written to unintended memory locations. This type of vulnerability typically manifests in array operations, string manipulations, or typed array handling within JavaScript engines.

Attack Vector

The attack requires local access to the target system. An attacker would need to craft malicious JavaScript code that triggers the vulnerable code path, causing the out-of-bounds write condition. This could be achieved through:

1. Executing specially crafted JavaScript in applications using Escargot as their JavaScript runtime
2. Providing malicious scripts to embedded systems or IoT devices running the vulnerable engine
3. Exploiting web applications or services that process user-supplied JavaScript through Escargot

The vulnerability manifests in the buffer handling logic of the Escargot engine. When specific conditions are met during JavaScript execution, the engine writes data beyond allocated buffer boundaries. Technical details regarding the specific vulnerable functions and exploitation methodology can be found in the GitHub Pull Request #1554 which addresses this issue.

Detection Methods for CVE-2026-25207

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications using the Escargot JavaScript engine
• Unusual memory access patterns or memory corruption errors in system logs
• Abnormal process behavior or unexpected child process spawning from Escargot-based applications
• Memory allocation anomalies detected by system monitoring tools

Detection Strategies

• Deploy memory corruption detection tools such as AddressSanitizer (ASan) during development and testing phases
• Implement application-level monitoring for unexpected JavaScript engine crashes or exceptions
• Utilize endpoint detection and response (EDR) solutions to identify exploitation attempts targeting memory corruption vulnerabilities
• Monitor for signs of code injection or unexpected code execution in processes utilizing Escargot

Monitoring Recommendations

• Enable verbose logging for applications utilizing the Escargot JavaScript engine
• Implement heap and stack integrity monitoring for critical applications
• Deploy SentinelOne's behavioral AI to detect post-exploitation activities
• Establish baseline behavior patterns for Escargot-based applications and alert on anomalies

How to Mitigate CVE-2026-25207

Immediate Actions Required

• Update the Escargot JavaScript engine to a version that includes the fix from Pull Request #1554
• Audit all systems and applications that utilize Escargot to identify vulnerable deployments
• Implement network segmentation to limit potential attack surface for systems running vulnerable versions
• Restrict local access to systems running Escargot where possible until patching is complete

Patch Information

Samsung has addressed this vulnerability through GitHub Pull Request #1554. Organizations using the Escargot JavaScript engine should:

1. Review the pull request to understand the code changes implemented
2. Update to a commit that includes the merged fix
3. Rebuild any applications or firmware that statically link against Escargot
4. Test thoroughly before deploying to production environments

Workarounds

• Limit execution of untrusted JavaScript code in Escargot-based applications until patching is complete
• Implement sandboxing mechanisms to contain potential exploitation attempts
• Deploy runtime application self-protection (RASP) solutions where available
• Consider temporarily disabling non-essential JavaScript functionality in affected applications

# Update Escargot to latest version with security fixes
git clone https://github.com/Samsung/escargot.git
cd escargot
git fetch origin
git log --oneline | head -20  # Verify commit history includes fix
# Rebuild with AddressSanitizer for additional protection during testing
cmake -DCMAKE_BUILD_TYPE=Debug -DESCARGOT_SANITIZER=address ..
make -j$(nproc)