CVE detail

CVE-2021-1621 — CVE-2021-1621

Published 2021-09-23 · Modified 2026-06-17 · Vendor cisco · Product ios_xe · Source nvd

HIGH

severity

CVSS-derived band

7.4

CVSS v3

0–10 scale

0.0036

EPSS probability

exploitation probability, 30d

29.0%

EPSS percentile

percentile vs all CVEs

NOT LISTED

CISA KEV

known exploited catalog

Description

A vulnerability in the Layer 2 punt code of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a queue wedge on an interface that receives specific Layer 2 frames, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of certain Layer 2 frames. An attacker could exploit this vulnerability by sending specific Layer 2 frames on the segment the router is connected to. A successful exploit could allow the attacker to cause a queue wedge on the interface, resulting in a DoS condition.

Remediation

Product	Vulnerable range	Fixed version	Advisory
Cisco Cisco IOS XE Software	—	not specified	advisory ↗

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.