CVE-2026-58305: Samsung Escargot Type Confusion Vulnerability

CVE-2026-58305 Overview

CVE-2026-58305 is a type confusion vulnerability [CWE-843] in Samsung Open Source Escargot, a lightweight JavaScript engine used in resource-constrained environments. The flaw allows attackers to manipulate pointers by causing the engine to access a resource using an incompatible type. Exploitation requires local access and user interaction, such as opening a crafted JavaScript file within an application that embeds Escargot. Successful attacks can corrupt process state, produce integrity impact, and trigger denial-of-service conditions in the host application. The issue affects Escargot builds prior to commit 779f6bedf58f334dec64b0a51ebb724b4708b84a.

Critical Impact
Type confusion in the Escargot JavaScript engine enables pointer manipulation, leading to integrity loss and application-level denial of service on affected embedded and desktop hosts.

Affected Products

Samsung Open Source Escargot JavaScript engine
Escargot builds prior to commit 779f6bedf58f334dec64b0a51ebb724b4708b84a
Applications and embedded systems that link the vulnerable Escargot library

Discovery Timeline

2026-07-09 - CVE-2026-58305 published to NVD
2026-07-09 - Last updated in NVD database

Technical Details for CVE-2026-58305

Vulnerability Analysis

The vulnerability is a type confusion condition inside the Escargot JavaScript engine. Escargot is a lightweight ECMAScript engine developed by Samsung for embedded and IoT platforms. Type confusion occurs when code treats a memory region as one data type while it actually holds another. In this case, the mismatch allows an attacker to influence pointer values that the engine dereferences during execution.

Because the engine parses attacker-controlled JavaScript, a crafted script can steer the interpreter into a mistyped access path. The resulting pointer manipulation produces integrity impact on engine internal state and a high availability impact through crashes or aborts. Confidentiality is not affected according to the published metrics. Exploitation requires local delivery of the malicious script and user interaction to trigger execution.

Root Cause

The root cause is an object or value handled through an incompatible type interpretation within Escargot's internal representation. The fix is delivered in upstream commit 779f6bedf58f334dec64b0a51ebb724b4708b84a, tracked in the project's GitHub Issue Report and GitHub Pull Request.

Attack Vector

An attacker crafts a JavaScript payload that abuses the mistyped access path when the script is loaded by an application embedding a vulnerable Escargot build. The attacker needs local access and must convince a user to open the payload. The engine then dereferences an attacker-influenced pointer, corrupting execution state and typically terminating the host process. No verified public exploit code is available at time of publication. Refer to the upstream references for reproduction details.

Detection Methods for CVE-2026-58305

Indicators of Compromise

Repeated crashes or abnormal termination of applications that embed the Escargot JavaScript engine.
Presence of Escargot binaries or libraries built from commits earlier than 779f6bedf58f334dec64b0a51ebb724b4708b84a.
Unexpected JavaScript files delivered to devices running Escargot-based runtimes or IoT firmware.

Detection Strategies

Inventory firmware images, containers, and applications that statically or dynamically link the Escargot library, and compare their build commit against the fixed revision.
Monitor process telemetry for crash signatures, segmentation faults, or abort signals originating from processes that host the Escargot interpreter.
Hunt for delivery of untrusted .js files to embedded devices through file transfer, USB, or update channels.

Monitoring Recommendations

Enable crash reporting on devices and hosts running Escargot to capture stack traces indicative of pointer misuse.
Alert on execution of JavaScript payloads from non-standard paths on IoT gateways or connected devices.
Track upstream Samsung Escargot commits and CVE feeds to catch related type confusion fixes.

How to Mitigate CVE-2026-58305

Immediate Actions Required

Update the Escargot engine to a build that includes commit 779f6bedf58f334dec64b0a51ebb724b4708b84a or later, then rebuild and redeploy dependent applications and firmware.
Identify every product and device that ships Escargot and coordinate patch rollout with vendors and integrators.
Restrict execution of untrusted JavaScript on affected devices until patches are deployed.

Patch Information

The upstream fix is committed to the Samsung Escargot repository under commit 779f6bedf58f334dec64b0a51ebb724b4708b84a. Details are tracked in the GitHub Issue Report and merged via the GitHub Pull Request. Downstream products embedding Escargot must integrate this commit and rebuild.

Workarounds

Disable or gate JavaScript execution features in applications that embed Escargot when possible.
Limit exposure by preventing local users from delivering arbitrary scripts to Escargot-based runtimes.
Apply application sandboxing or process isolation so crashes triggered by malicious scripts do not disrupt other services.

bash

# Verify the Escargot build against the fixed commit
cd escargot
git fetch origin
git log --oneline | grep 779f6bedf58f334dec64b0a51ebb724b4708b84a
git checkout 779f6bedf58f334dec64b0a51ebb724b4708b84a
# Rebuild the engine and dependent applications
./build.sh