🔴 Critical Vulnerability: CVE-2021-34770 — cisco

Vulnerability Snapshot

CVE-2021-34770 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: ios_xe, catalyst_9800, catalyst_9800-40, catalyst_9800-40_wireless_controller, catalyst_9800-80, plus 5 other product variants.

Executive Summary

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, remote attacker to execute arbitrary code with administrative privileges or cause a denial of service (DoS) condition on an affected device. The vulnerability is due to a logic error that occurs during the validation of CAPWAP packets. An attacker could exploit this vulnerability by sending a crafted CAPWAP packet to an affected device. A successful exploit could allow the attacker to execute arbitrary code with administrative privileges or cause the affected device to crash and reload, resulting in a DoS condition.

Why It Matters

CVE-2021-34770 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 10/10

Affected Technologies

Vendors: cisco

Products: ios_xe, catalyst_9800, catalyst_9800-40, catalyst_9800-40_wireless_controller, catalyst_9800-80, catalyst_9800-80_wireless_controller, catalyst_9800-cl, catalyst_9800-l, catalyst_9800-l-c, catalyst_9800-l-f, catalyst_9800_embedded_wireless_controller

🛡️What Defenders Should Check

Check if you are affected — Review your asset inventory for products listed in CVE-2021-34770.

Apply available patches — Visit vendor advisories for the latest security updates.

Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

Use Vulnios to continuously monitor your exposure to CVE-2021-34770 and similar vulnerabilities.

References & Sources

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ewlc-capwap-rce-LYgj8Kf

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

ios_xecatalyst_9800catalyst_9800-40catalyst_9800-40_wireless_controllercatalyst_9800-80catalyst_9800-80_wireless_controllercatalyst_9800-clcatalyst_9800-lcatalyst_9800-l-ccatalyst_9800-l-f

Sources

NVD / NIST

Related Threat Alerts

Frequently Asked Questions

What is CVE-2021-34770?

CVE-2021-34770 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unaut

Am I affected?

Check whether your environment runs ios_xe, catalyst_9800, catalyst_9800-40, catalyst_9800-40_wireless_controller, catalyst_9800-80. 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-2021-34770. 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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Critical Vulnerability: CVE-2021-34770 — cisco — ios_xe, catalyst_9800