Is CVE-1999-0347 actively exploited?

A proof-of-concept exploit is publicly available for CVE-1999-0347, but active exploitation has not been confirmed.

Can CVE-1999-0347 be exploited remotely?

Yes. CVE-1999-0347 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-1999-0347?

CVE-1999-0347 has a CVSS score of 10.0 (CRITICAL).

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CVE-1999-0347

NVD-CWE-OtherPublished: January 26, 1999· Updated: Jun 16, 2026

10.0

CVSS v3.1

Official Description

Internet Explorer 4.01 allows remote attackers to read local files and spoof web pages via a "%01" character in an "about:" Javascript URL, which causes Internet Explorer to use the domain specified after the character.

NVD Source

Technical Analysis

CVE-1999-0347 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A proof-of-concept (PoC) exploit exists for CVE-1999-0347. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.