CVE-2026-33566 Code injection in LogonTracer

What is CVE-2026-33566?

CVE-2026-33566 is a medium-severity code injection vulnerability in Japan Computer Emergency Response Team Coordination Center (JPCERT/CC) LogonTracer, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

There is a cypher injection issue in LogonTracer prior to v2.0.0. If specially crafted Windows event log data is loaded, the contents of the database may be altered.

Weakness: CWE-943

Which versions are affected by CVE-2026-33566?

It affects 1 product.

Products include Jpcert Logontracer.

How do I fix CVE-2026-33566?

No fix has been published for CVE-2026-33566 yet. Limit exposure of the affected software until one is available.

Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.

Is CVE-2026-33566 being exploited?

There is no known exploitation of CVE-2026-33566 in the wild and no public exploit code.

Other vulnerabilities in Japan Computer Emergency Response Team Coordination Center (JPCERT/CC) LogonTracer

• CVE-2018-16167 Command injection in LogonTracer Critical 9.8
• CVE-2018-16168 Code injection in LogonTracer Critical 9.8
• CVE-2018-16166 XML external entity in LogonTracer High 8.8
• CVE-2026-33277 An OS command Injection issue exists in LogonTracer prior to v2.0.0. High 8.7
• CVE-2018-16165 Cross-site scripting in LogonTracer Medium 6.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-vqg4-6jf2-58rx.