Critical severity · published Sep 15, 2026
CVE-2026-89040
Tencent Mass Service Engine in Cluster (MSEC) path traversal
9.8
CVSS
1.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 67% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MS
Mass Service Engine in Cluster (MSEC) · Tencent
0 · source: vendor
Affected product
MS
Mass Service Engine in Cluster (MSEC)
Tencent
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89040
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-89040
github.com
https://github.com/Tencent/MSEC
raw.githubusercontent.com
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-258-02.json
www.cve.org
https://www.cve.org/CVERecord?id=CVE-2026-89040