Vulnerability · Published Sep 15, 2026 · Assigned by cisa-cg
CVE-2026-89040Tencent Mass Service Engine in Cluster (MSEC) path traversal
Critical 9.8
In plain English
A critical-severity path traversal in Mass Service Engine in Cluster (MSEC) from Tencent. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 67% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)1.1%top 33.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Tencent | Mass Service Engine in Cluster (MSEC) | 0 – before * |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H