PatchTheCVECVE-2021-42071: In Visual Tools DVR VX16 4.2.28.0, an unauthenticated attacker can achieve remote command execution via shell
CVE-2021-42071 is a critical-severity flaw (CVSS 9.8) affecting dvr vx16 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
In Visual Tools DVR VX16 4.2.28.0, an unauthenticated attacker can achieve remote command execution via shell metacharacters in the cgi-bin/slogin/login.py User-Agent HTTP header.
Why this priority
- Critical severity
- EPSS top 1%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 69.9% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-78 |
| Published | 2021-10-07 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Exploit-DB: Visual Tools DVR VX16 4.2.28.0 - OS Command Injection (Unauthenticated)
- Nuclei scan template: Visual Tools DVR VX16 4.2.28.0 - Unauthenticated OS Command Injection
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-42071?
dvr vx16 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2021-42071 being exploited?
CVE-2021-42071 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-42071 affect?
CVE-2021-42071 affects dvr vx16 firmware. Severity is critical (CVSS 9.8). In Visual Tools DVR VX16 4.2.28.0, an unauthenticated attacker can achieve remote command execution via shell metacharacters in the cgi-bin/slogin/login.py User-Agent HTTP header.
How urgent is CVE-2021-42071?
Priority 69/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action