Out-of-Bounds Read/Write in Samsung Escargot

Executive Summary

CVE-2026-58304 is an out-of-bounds (OOB) read and write vulnerability in the Escargot JavaScript engine's ArrayBuffer.prototype.transfer implementation. It occurs when transferring an ArrayBuffer with a specified maxByteLength that exceeds the original buffer's size without proper validation.

This flaw allows an attacker to read and write memory beyond the intended buffer limits, potentially leading to memory corruption or arbitrary code execution.

The issue was fixed by adding checks to ensure the new byte length does not exceed the original buffer's length for non-resizable ArrayBuffers, throwing a RangeError if it does.

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Impact Analysis

This vulnerability can lead to serious security impacts including memory corruption and arbitrary code execution.

An attacker exploiting this flaw can write arbitrary data beyond the buffer's limits and read sensitive memory contents, potentially accessing confidential information or manipulating program behavior.

In debug builds, it causes assertion failures, while in release builds, it enables out-of-bounds read and write operations, increasing the risk of exploitation.

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Detection Guidance

This vulnerability is an out-of-bounds read and write issue in the Escargot JavaScript engine's ArrayBuffer.prototype.transfer implementation. Detection involves identifying if your system is running a vulnerable version of Escargot (before commit 779f6bedf58f334dec64b0a51ebb724b4708b84a) and if the engine is compiled in debug mode, which triggers assertion failures.

Since the vulnerability manifests as crashes or assertion failures in debug builds, monitoring for such crashes or assertion logs related to ArrayBuffer transfer operations can help detect exploitation attempts.

Specific commands to detect this vulnerability are not provided in the available resources. However, general steps include:

• Check the Escargot version or commit hash in your environment to confirm if it is before the fixed commit.
• Monitor application logs for assertion failures or crashes related to ArrayBuffer transfers.
• Use debugging or memory analysis tools to detect out-of-bounds memory accesses during ArrayBuffer operations.

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Mitigation Strategies

The primary mitigation is to update the Escargot JavaScript engine to a version that includes the fix committed on May 27, 2026, which ensures proper validation of ArrayBuffer transfer byte lengths.

The fix introduces a check that throws a RangeError if the new byte length exceeds the original buffer's length for non-resizable ArrayBuffers, preventing out-of-bounds reads and writes.

Until the update can be applied, consider disabling or restricting the use of ArrayBuffer transfer operations in your environment to reduce exposure.

Additionally, running Escargot in release mode rather than debug mode may reduce the risk of assertion failures, but does not eliminate the vulnerability.

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Compliance Impact

The provided information does not specify any direct impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

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