CVE-2021-42071: In Visual Tools DVR VX16 4.2.28.0, an unauthenticated attacker can achieve remote command execution via shell metacharacters in the…
Noroxi assessment
Priority: This week (action score 60/100)
- A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
- Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 69.8% (FIRST EPSS); higher than 99.3% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to the record, no fixed version is available yet.
Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Oct 7, 2021
- Updated
- Jun 17, 2026
- EPSS
- 69.8% · 99th percentile
- CWE
- CWE-78
Report tools
Action score
60
Don’t wait for the next maintenance window.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 21 / 30 · 69.8%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| visual-tools | dvr vx16 firmware | cpe:2.3:o:visual-tools:dvr_vx16_firmware |
| visual-tools | dvr vx16 | cpe:2.3:h:visual-tools:dvr_vx16 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- visual-tools dvr vx16 firmware4.2.28.0
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Exploit-DB entry ×1
- Nuclei detection template ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | webapps | 2021-07-06 |
| Nuclei detection template | Nuclei template CVE-2021-42071 | — |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-94 d
- Published
- TodayNov 12, 2026+1862 d
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
User input is inserted as text into a shell command. The shell may interpret special characters in the input as part of the command.
The bug in code
The whole CWE-78 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const host = req.body.host;
exec("ping -c 1 " + host, onResult);Fixed
const host = req.body.host;
if (!/^[a-z0-9.-]{1,253}$/i.test(host)) return res.sendStatus(400);
execFile("ping", ["-c", "1", host], onResult);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Command DelimitersCAPEC-15likelihood: High · High
- Exploiting Multiple Input Interpretation LayersCAPEC-43likelihood: Medium · High
- Argument InjectionCAPEC-6likelihood: High · High
- OS Command InjectionCAPEC-88likelihood: High · High
ATT&CK techniques
—
Change log (0)
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.