THREATPORT/VULNERABILITY/CVE-2021-4473
CRITICAL SEVERITY

CVE-2021-4473

Tianxin Internet Behavior Management System vulnerability

CVSS
9.8
EPSS
6.2%
EPSS pct
93th
Exploited
No known
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).
Affected vendor
Topsecgroup
Affected product
Tianxin Internet Behavior Management System
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-78 — OS Command Injection
Published
2026-04-07

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 6.2% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 93% of all scored CVEs.

Check your external exposure to CVE-2021-4473

  • Confirm whether Topsecgroup Tianxin Internet Behavior Management System is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2021-4473.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-4473

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2021-4473 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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