Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2021-1472

Cisco Small Business RV Series Routers Vulnerabilities

Cisco Small Business RV Series Router Firmware

Watch CVE-2021-1472 Browse KEV feed
Severity
CVSS 5.3 · Medium
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
72.0%
First observed
03 Jul 2026
Last observed
04 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-1472 is an unauthenticated Cisco Small Business RV Series Routers Vulnerabilities. Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Cisco Small Business RV Series Router Firmware.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers

Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote attacker could execute arbitrary commands or bypass authentication and upload files on an affected device.

For more information about these vulnerabilities, see the Details section of this advisory.

View vendor advisory (opens in new tab)
Published
08 Apr 2021
Exploitation Reported
03 Jul 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

edge nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Previdian

Recorded 03 Jul 2026

Previdian independently recorded this as exploited after first seeing it in honeypot sensors.

Active exploitation observed

Previdian sensor

First observed 03 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Previdian Sensors First 2026-07-30 15:50 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

19

Attempts observed

12

Unique attacker IPs

9

Attacker countries

BG · CH · DE · FI · FR · JP · NL · TM · US

13

Sensors observed

CVE-2021-1472 exploitation attempts over the last 85 days

Daily events observed by Previdian sensors

Updated 10 Oct 2026

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18 Jul 4 Aug 21 Aug 7 Sep 10 Oct

First observed 03 Jul 2026 · Last observed 04 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
1
12
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/cisco_rv_series_authbypass_and_rce.rb 28 Apr 2025
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-1472.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

5.3 Medium

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS

72.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Restriction of Operations within the Bounds of a Memory Buffer CWE-119 Improper Authentication CWE-287

All CVSS Scores

CVSS v3.1 5.3 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v2.0 7.5 High

AV:N/AC:L/Au:N/C:P/I:P/A:P

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Cisco Small Business RV Series - OS Command Injection

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 04:21 UTC

    Indicators of compromise added (17)

    Indicators of compromise recorded

  2. 04:21 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 14:20 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 15:02 UTC

    Metasploit module available

    Exploit module available

  5. 00:00 UTC

    Nuclei template available

    Scanner coverage available

  6. 04:06 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-1472

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-1472",
  "confidence": "Confirmed",
  "cvss_score": 5.3,
  "cvss_estimated": false,
  "epss_score": 0.72028,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 19, "sensors": 13 }
}