Vulnerability Snapshot
CVE-2021-34730 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Affected technology: application_extension_platform, rv110w_wireless-n_vpn_firewall_firmware, rv110w_wireless-n_vpn_firewall, rv130_vpn_router_firmware, rv130_vpn_router, plus 4 other product variants.
Executive Summary
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.
Why It Matters
CVE-2021-34730 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.8/10
Affected Technologies
Vendors: cisco
Products: application_extension_platform, rv110w_wireless-n_vpn_firewall_firmware, rv110w_wireless-n_vpn_firewall, rv130_vpn_router_firmware, rv130_vpn_router, rv130w_wireless-n_multifunction_vpn_router_firmware, rv130w_wireless-n_multifunction_vpn_router, rv215w_wireless-n_vpn_router_firmware, rv215w_wireless-n_vpn_router
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2021-34730 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for SBOM-based CVE matching and Vulnios CVE feed continuous monitoring against your asset inventory. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Affected Products
Sources
Related Threat Alerts
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- Critical Vulnerability: CVE-2025-20358 — cisco — unified_contact_center_express
- Critical Vulnerability: CVE-2025-20363 — cisco — ios_xr, asr_9001
- Critical Vulnerability: CVE-2024-20412 — cisco — secure_firewall_threat_defense, firepower_1000
- Critical Vulnerability: CVE-2021-40113 — cisco — catalyst_pon_switch_cgp-ont-1p_firmware, catalyst_pon_switch_cgp-ont-1p
Frequently Asked Questions
What is CVE-2021-34730?
CVE-2021-34730 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. 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 cod
Am I affected?
Check whether your environment runs application_extension_platform, rv110w_wireless-n_vpn_firewall_firmware, rv110w_wireless-n_vpn_firewall, rv130_vpn_router_firmware, rv130_vpn_router. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2021-34730. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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