RCE in Beijing Topsec Network Security Technology Co., Ltd. Tianxin Internet Behavior Management System
CVE-2021-4473
Tianxin Internet Behavior Management System contains a command injection vulnerability in the Reporter component endpoint that allows unauthenticated attackers to execute arbitrary commands by supplying a crafted objClass parameter containing shell metacharacters and output redirection. Attackers can exploit this vulnerability to write malicious PHP files into the web root and achieve remote code execution with the privileges of the web server process. This vulnerability has been fixed in version NACFirmware_4.0.0.7_20210716.180815_topsec_0_basic.bin. Exploitation evidence was first observed by the Shadowserver Foundation on 2024-06-01 (UTC).
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.062 (93.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 93rd percentile — 93.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.062 · newest: 0.062 · change: 0.000
Affected products
Weakness classification (CWE)
References
- www.cnvd.org.cn/flaw/show/CNVD-2021-41972 (Third Party Advisory, government-resource)
- www.cnvd.org.cn/patchInfo/show/280166 (Patch, patch)
- cn-sec.com/archives/4631959.html (Exploit, technical-description, Third Party Advisory, exploit)
- avd.aliyun.com/detail (Third Party Advisory, third-party-advisory)
- www.vulncheck.com/advisories/tianxin-internet-behavior-management-system-comman… (VDB Entry, Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2021-4473?
- CVE-2021-4473 is a critical-severity vulnerability in Beijing Topsec Network Security Technology Co., Ltd. Tianxin Internet Behavior Management System, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-04-07.
- How severe is CVE-2021-4473?
- Critical severity. CVSS v3 base score is 9.8 out of 10.