CVE-2026-58307 Overview
CVE-2026-58307 is an out-of-bounds read and reachable assertion vulnerability in Samsung Open Source Escargot, a lightweight JavaScript engine designed for resource-constrained devices. The flaw allows attackers to overread buffer memory and manipulate input data through crafted JavaScript. Exploitation requires local access and user interaction to process malicious input. The issue affects Escargot versions prior to commit 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c. The weakness is classified under [CWE-125] Out-of-bounds Read.
Critical Impact
Successful exploitation can trigger process termination through reachable assertions or leak adjacent memory contents, impacting availability and integrity of applications embedding the Escargot engine.
Affected Products
- Samsung Open Source Escargot JavaScript engine
- Escargot builds before commit 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c
- Applications and IoT devices embedding vulnerable Escargot builds
Discovery Timeline
- 2026-07-09 - CVE-2026-58307 published to NVD
- 2026-07-09 - Last updated in NVD database
Technical Details for CVE-2026-58307
Vulnerability Analysis
Escargot is a compact JavaScript engine maintained by Samsung and used in embedded and IoT contexts. The vulnerability combines two related weaknesses: an out-of-bounds read and a reachable assertion. When Escargot processes crafted JavaScript input, the engine reads memory outside the intended buffer bounds. In parallel, malformed input can reach an assertion path that terminates the process. The result is a high impact on availability and a limited impact on integrity, while confidentiality is not affected according to the assigned CVSS vector.
The attack surface is local because Escargot must ingest the malicious script through an embedding host, and user interaction is required to execute the payload. See the GitHub Issue Discussion for the reproduction context.
Root Cause
The root cause is missing or insufficient bounds validation when the engine parses or executes specific JavaScript constructs. The condition also exposes an assertion that developers assumed unreachable, which crafted input can trigger. The upstream fix landed in commit 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c and is documented in the GitHub Pull Request.
Attack Vector
An attacker crafts JavaScript that, when interpreted by Escargot, drives the engine into the vulnerable code path. Delivery requires a local vector such as a script file, embedded application input, or content processed by an Escargot-hosted runtime. User interaction is required to load or execute the payload. Refer to the upstream issue and patch for technical reproduction details; no verified public exploit is available at this time.
Detection Methods for CVE-2026-58307
Indicators of Compromise
- Unexpected termination or assertion failure messages emitted by processes embedding the Escargot runtime.
- Core dumps or crash reports referencing Escargot symbol names originating from JavaScript parsing or execution paths.
- Repeated crashes correlated with newly introduced or externally sourced JavaScript content.
Detection Strategies
- Inventory software and firmware images to identify Escargot builds predating commit 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c.
- Enable AddressSanitizer or equivalent memory instrumentation in test builds to flag out-of-bounds reads during fuzzing.
- Monitor application telemetry for abnormal exit codes or SIGABRT signals from Escargot-hosted processes.
Monitoring Recommendations
- Forward host crash logs and application telemetry to a centralized logging pipeline for correlation.
- Track integrity of JavaScript content delivered to embedded devices running Escargot.
- Alert on repeated abnormal process terminations on devices that execute untrusted scripts.
How to Mitigate CVE-2026-58307
Immediate Actions Required
- Update Escargot to a build that includes commit 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c or later.
- Rebuild and redistribute firmware or applications that statically link against a vulnerable Escargot version.
- Restrict execution of untrusted JavaScript on devices embedding Escargot until patches are deployed.
Patch Information
The fix is committed upstream at 2dee22f5c7b8bf31cb7252d7731fae8c07f2842c. Downstream integrators should pull the patched source from the GitHub Pull Request and rebuild affected products. No vendor-specific advisory URLs are listed in the NVD entry.
Workarounds
- Disable or sandbox Escargot-hosted script execution where JavaScript input cannot be fully trusted.
- Apply input validation at the host application layer to reject malformed or oversized script payloads.
- Isolate Escargot processes with least-privilege accounts to limit impact of assertion-driven termination.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
