No exploitation reported

CVE-2021-1373

No exploitation reported by the sources we read.

Published2021-03-24
WeaknessCWE-126

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 Wireless Controller Software for the Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition of an affected device. The vulnerability is due to insufficient validation of CAPWAP packets. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition.

Timeline

dates in UTC

2021-03-2421:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 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-2021-1373?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-1373?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
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
16.12	= 16.12.1	no fix published	NVD
16.12	= 16.12.1s	no fix published	NVD
16.12	= 16.12.1t	no fix published	NVD
16.12	= 16.12.2s	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 decisionnone2024-11-08
OpenCVESSVC decisionnone—
CNACVSS 3.18.6read 2026-10-23
NVDCVSS 3.18.6read 2026-10-23
NVDCVSS 2.07.8read 2026-10-23
CNAweakness (CWE)CWE-126read 2026-10-23
FIRST EPSSEPSS score1.5 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Published: 2021-03-24
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-1373?

Is CVE-2021-1373 actively exploited?

Active exploitation of CVE-2021-1373 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-1373?

CVE-2021-1373 has a CVSS v3 base score of 8.6 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.

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