CVE-2026-25209: Samsung Escargot Information Disclosure

CVE-2026-25209 Overview

CVE-2026-25209 is an out-of-bounds read vulnerability discovered in Samsung's Open Source Escargot JavaScript engine. This vulnerability allows attackers to trigger resource leak exposure by reading memory beyond intended boundaries. Escargot is a lightweight JavaScript engine primarily designed for embedded systems and IoT devices, making this vulnerability particularly concerning for resource-constrained environments where memory safety is critical.

Critical Impact

Successful exploitation could allow attackers to leak sensitive information from memory and potentially cause service disruption through improper memory access in JavaScript engine operations.

Affected Products

• Samsung Open Source Escargot (commit 97e8115ab1110bc502b4b5e4a0c689a71520d335)

Discovery Timeline

• April 13, 2026 - CVE-2026-25209 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2026-25209

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-bounds Read), a common memory safety issue where software reads data past the end or before the beginning of an intended buffer. In the context of the Escargot JavaScript engine, this flaw could be triggered during JavaScript parsing or execution operations, potentially exposing internal memory contents to an attacker.

Out-of-bounds read vulnerabilities in JavaScript engines are particularly dangerous because they can be exploited through maliciously crafted JavaScript code. Attackers could potentially leverage this vulnerability to bypass memory isolation protections, leak sensitive heap or stack data, or gather information useful for crafting more sophisticated attacks.

Root Cause

The root cause stems from insufficient boundary validation when accessing memory buffers within the Escargot JavaScript engine. The engine fails to properly validate array indices or pointer offsets before performing read operations, allowing memory access outside the intended data structure boundaries. This type of vulnerability typically occurs in performance-optimized code paths where bounds checking may have been inadvertently omitted or implemented incorrectly.

Attack Vector

The attack vector is network-based, allowing remote exploitation without requiring user interaction or prior authentication. An attacker could deliver malicious JavaScript code to a system running the vulnerable Escargot engine through various means:

1. Serving malicious JavaScript through a compromised or attacker-controlled web server
2. Embedding exploit code in documents or applications that utilize Escargot for JavaScript processing
3. Injecting malicious JavaScript into legitimate content through man-in-the-middle attacks

The vulnerability requires specific conditions to exploit (high attack complexity), as the attacker must craft JavaScript that triggers the precise out-of-bounds read condition. Technical details regarding the specific vulnerable code paths can be found in the GitHub Pull Request for Escargot.

Detection Methods for CVE-2026-25209

Indicators of Compromise

• Unexpected crashes or segmentation faults in applications utilizing the Escargot JavaScript engine
• Anomalous memory access patterns detected by memory sanitizers or security monitoring tools
• JavaScript payloads with unusual array access patterns or buffer manipulation operations
• Process memory dumps indicating data leakage from heap or stack regions

Detection Strategies

• Deploy runtime memory protection tools (AddressSanitizer, Valgrind) to detect out-of-bounds memory access attempts
• Monitor Escargot-based applications for unusual behavior or unexpected termination
• Implement JavaScript static analysis to identify potentially malicious code patterns before execution
• Review application logs for errors related to memory access violations or buffer operations

Monitoring Recommendations

• Enable verbose logging in applications utilizing the Escargot JavaScript engine to capture memory-related errors
• Implement endpoint detection and response (EDR) solutions to monitor for exploitation attempts
• Set up alerts for process crashes or memory corruption events in systems running Escargot
• Monitor network traffic for delivery of suspicious JavaScript content to vulnerable endpoints

How to Mitigate CVE-2026-25209

Immediate Actions Required

• Identify all systems and applications utilizing the Samsung Escargot JavaScript engine at commit 97e8115ab1110bc502b4b5e4a0c689a71520d335 or earlier
• Review the patch details in the GitHub Pull Request for Escargot and update to a patched version
• Implement network segmentation to limit exposure of vulnerable systems until patches can be applied
• Consider disabling or restricting JavaScript execution in affected applications where feasible

Patch Information

Samsung has addressed this vulnerability through a code fix available in the Escargot repository. Organizations should update their Escargot installation to incorporate the fix from the GitHub Pull Request #1554. The patch adds proper boundary validation to prevent out-of-bounds memory reads.

To update, rebuild the Escargot engine from source using a commit that includes the security fix, then redeploy affected applications with the updated library.

Workarounds

• Restrict or sandbox JavaScript execution in applications using the vulnerable Escargot engine version
• Implement Content Security Policy (CSP) to limit JavaScript sources to trusted origins only
• Deploy Web Application Firewalls (WAF) with rules to filter potentially malicious JavaScript patterns
• Run Escargot-based applications in isolated environments with reduced privileges to minimize impact of successful exploitation

# Build updated Escargot from source with security fix
git clone https://github.com/Samsung/escargot.git
cd escargot
git checkout main  # Ensure using latest version with security fixes
cmake -DESCARGOT_MODE=release -B build
cmake --build build