No exploitation reported

CVE-2021-34770

No exploitation reported by the sources we read.

Published2021-09-23
WeaknessCWE-122 · 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 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.

Timeline

dates in UTC

2021-09-2303:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 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-2021-34770?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-34770?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Cisco ios xeversion to verify

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD
3.15	= 3.15.1xbs	no fix published	NVD
3.15	= 3.15.2xbs	no fix published	NVD
16.6	= 16.6.4s	no fix published	NVD
16.10	= 16.10.1	no fix published	NVD
16.10	= 16.10.1e	no fix published	NVD
16.10	= 16.10.1s	no fix published	NVD
16.11	= 16.11.1	no fix published	NVD
16.11	= 16.11.1a	no fix published	NVD
16.11	= 16.11.1b	no fix published	NVD
16.11	= 16.11.1c	no fix published	NVD
16.11	= 16.11.2	no fix published	NVD

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

Fix

Advisories and patches

tools.cisco.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-11-07
OpenCVESSVC decisionnone—
CNACVSS 3.110read 2026-10-23
NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.09read 2026-10-23
CNAweakness (CWE)CWE-122read 2026-10-23
NVDweakness (CWE)CWE-787read 2026-10-23
FIRST EPSSEPSS score3.0 %2026-10-23

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: 2021-09-23
Last Modified: 2026-06-17
NVD status: Analyzed

Frequently asked questions

What is CVE-2021-34770?

Is CVE-2021-34770 actively exploited?

Active exploitation of CVE-2021-34770 has not been confirmed. Its EPSS score was 3.0% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-34770?

CVE-2021-34770 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.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database