CVE-2026-89040

Critical CVSS 9.8

Published 2026-09-15 · last changed 2026-09-22

The fix

We hold no Microsoft remediation data for CVE-2026-89040, which normally means it is not a Windows CVE. For non-Microsoft software the fix is the vendor's own updated release, and the affected versions are listed below.

What it is

Tencent Mass Service Engine in Cluster (MSEC) allows a remote, unauthenticated attacker to send a crafted POST request including ../ and gain root access on the target device. An attacker who uploads a webshell can execute arbitrary code as root.

Sources

NVD record for CVE-2026-89040

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H