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Public proof of concept

CVE-2021-34730

A public proof of concept exists; no exploitation attested.

  • Published2021-08-18
  • WeaknessCWE-121 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability in the Universal Plug-and-Play (UPnP) service of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an unauthenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of incoming UPnP traffic. An attacker could exploit this vulnerability by sending a crafted UPnP request to an affected device. A successful exploit could allow the attacker to execute arbitrary code as the root user on the underlying operating system or cause the device to reload, resulting in a DoS condition. Cisco has not released software updates that address this vulnerability.

Timeline

dates in UTC
  1. 2021-08-1820:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-04 03:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-34730?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-34730?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Cisco application extension platform
BranchAffectedFixed in
1.0= 1.0.3.55no fix published
Cisco rv110w wireless-n vpn firewall firmwareversion to verify
BranchAffectedFixed in
—all versionsno fix published
Cisco rv130 vpn router firmwareversion to verify
BranchAffectedFixed in
—all versionsno fix published

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As cisco, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Cisco Small Business RV Series Router Firmware

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2021-08-18

Fix

Advisories and patches

Detection

read 2026-11-03 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedbadmonkey7/CVE-2021-34730
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2024-11-07
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.19.8known since 2026-10-23
  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.010read 2026-10-23
  • CNAweakness (CWE)CWE-121known since 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score18.5 %read 2026-11-03
  • PoC-in-GitHubproof of concept1read 2026-11-03
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-08-18
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-9c26-qcv5-q5qj

Frequently asked questions

What is CVE-2021-34730?

A vulnerability in the Universal Plug-and-Play (UPnP) service of Cisco Small Business RV110W, RV130, RV130W, and RV215W Routers could allow an unauthenticated, remote attacker to execute arbitrary code or cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of incoming UPnP traffic. An attacker could exploit this vulnerability by sending a crafted UPnP request to an affected device. A successful exploit could allow the attacker to execute arbitrary code as the root user on the underlying operating system or cause the device to reload, resulting in a DoS condition. Cisco has not released software updates that address this vulnerability.

Is CVE-2021-34730 actively exploited?

Active exploitation of CVE-2021-34730 has not been confirmed. Its EPSS score was 18.5% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-34730?

CVE-2021-34730 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record