CVE-2026-58304 Overview
CVE-2026-58304 is an out-of-bounds read and out-of-bounds write vulnerability in Samsung Open Source Escargot, a lightweight JavaScript engine designed for resource-constrained environments. The flaw allows buffer overflow conditions that can corrupt adjacent memory or leak sensitive process data. Exploitation requires local access and user interaction, typically through processing a malicious JavaScript payload. The issue is tracked under CWE-125 and affects all Escargot builds prior to commit 779f6bedf58f334dec64b0a51ebb724b4708b84a. Samsung has merged a fix through pull request #1580 in the upstream repository.
Critical Impact
An attacker who convinces a user to execute crafted JavaScript within a vulnerable Escargot instance can trigger memory corruption resulting in high availability impact and potential integrity loss.
Affected Products
- Samsung Open Source Escargot JavaScript engine
- All commits prior to 779f6bedf58f334dec64b0a51ebb724b4708b84a
- Embedded devices and applications integrating vulnerable Escargot builds
Discovery Timeline
- 2026-07-09 - CVE-2026-58304 published to NVD
- 2026-07-09 - Last updated in NVD database
Technical Details for CVE-2026-58304
Vulnerability Analysis
The vulnerability resides in Samsung's Escargot JavaScript engine, which is optimized for IoT and embedded platforms with limited memory. Escargot parses and executes JavaScript through a custom interpreter and bytecode runtime. The defect enables both out-of-bounds read and out-of-bounds write operations against internal buffers during script execution.
An out-of-bounds read can expose stack or heap contents from adjacent allocations, while the out-of-bounds write allows an attacker to modify memory beyond the intended buffer boundary. The engine's local attack vector, combined with the required user interaction, indicates the flaw triggers when a victim loads or runs attacker-supplied JavaScript. Successful exploitation most reliably produces a denial-of-service condition through process crash, with partial integrity impact against runtime data structures.
For complete technical context, review the GitHub Issue Report and the GitHub Pull Request.
Root Cause
The root cause is missing or insufficient bounds checking on a buffer access path within the Escargot runtime, classified under [CWE-125] (Out-of-bounds Read). The absence of length validation permits read and write operations to cross the allocated boundary of the target buffer.
Attack Vector
Exploitation requires local access to a system running a vulnerable Escargot build and user interaction to execute a crafted JavaScript file. The engine processes the malicious input, triggering the buffer overflow condition during interpretation or bytecode handling. No authentication is required. The vulnerability does not enable network-based remote exploitation on its own, but embedded products that expose Escargot to attacker-controlled content increase the practical attack surface.
Detection Methods for CVE-2026-58304
Indicators of Compromise
- Unexpected crashes or segmentation faults in processes hosting the Escargot JavaScript engine
- Anomalous JavaScript files delivered to or executed by embedded devices running Escargot
- Core dumps referencing Escargot runtime modules with heap or stack corruption signatures
Detection Strategies
- Inventory all applications, firmware images, and IoT devices bundling Escargot and identify builds predating commit 779f6bedf58f334dec64b0a51ebb724b4708b84a
- Monitor host telemetry for repeated crashes of processes linked to the Escargot library or libescargot shared object
- Inspect JavaScript payloads delivered to embedded endpoints for unusual typed array manipulations or oversized index operations
Monitoring Recommendations
- Enable crash reporting and core dump collection for services embedding Escargot to capture forensic evidence of exploitation attempts
- Aggregate process termination and memory error events into centralized logging for correlation across fleets of embedded devices
- Track upstream Escargot releases and CVE advisories to detect newly disclosed related defects
How to Mitigate CVE-2026-58304
Immediate Actions Required
- Update Escargot to a build that includes commit 779f6bedf58f334dec64b0a51ebb724b4708b84a or later
- Rebuild and redeploy any downstream applications or firmware images that statically link the vulnerable Escargot library
- Restrict local execution of untrusted JavaScript on devices running Escargot until the patch is applied
Patch Information
Samsung has resolved the issue in the upstream Escargot repository through GitHub Pull Request #1580. Downstream integrators must pull the fixed commit 779f6bedf58f334dec64b0a51ebb724b4708b84a and rebuild affected products. Refer to the GitHub Issue Report for the original defect description.
Workarounds
- Block delivery of untrusted JavaScript to devices and applications that embed Escargot
- Enforce least-privilege execution contexts so that Escargot processes run without elevated permissions
- Enable operating system memory protections such as ASLR and stack canaries on platforms hosting Escargot to reduce exploitability
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
