CVE-2026-105578: Microsoft JScript integer overflow allows code execution

CVE-2026-105578 · Severity: high · CVSS 7.5 · Published 2026-11-10

Microsoft JScript, a scripting engine used in Windows and Internet Explorer, contains an integer overflow vulnerability that allows an attacker to execute arbitrary code remotely. An attacker can exploit this flaw by crafting malicious code that triggers the overflow, potentially gaining full control of an affected system without user authentication.

Technologies: Microsoft JScript. Vendors: Microsoft.

Quick answers

Is CVE-2026-105578 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-105578 being exploited in the wild.
How severe is CVE-2026-105578?
High severity, with a CVSS score of 7.5, published 10 November 2026.
Which products and versions are affected?
Microsoft JScript.
Is there a fix for CVE-2026-105578?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-105578 attacked?
It is attacked over the network.
Am I affected by CVE-2026-105578?
Check whether you run Microsoft JScript. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An integer overflow or wraparound in Microsoft JScript's numeric handling allows remote code execution via network attack vector. The vulnerability requires no authentication and can be triggered through malicious script content, granting the attacker arbitrary code execution in the JScript engine's context.

Affected products

  • Microsoft JScript

Timeline

  • 2026-11-10: disclosed

References

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