CVE-2021-1403: Cisco IOS XE Software Web UI Cross-Site WebSocket Hijacking Vulnerability

Severity: high (CVSS 7.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-03-24 · updated 2026-06-17
Weakness: CWE-345

Description

A vulnerability in the web UI feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct a cross-site WebSocket hijacking (CSWSH) attack and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient HTTP protections in the web UI on an affected device. An attacker could exploit this vulnerability by persuading an authenticated user of the web UI to follow a crafted link. A successful exploit could allow the attacker to corrupt memory on the affected device, forcing it to reload and causing a DoS condition.

Affected products

Cisco IOS XE: 3.15.1xbs, 3.15.2xbs, 16.3.1, 16.3.1a, 16.3.2, 16.3.3 (+117)

References

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