CVE-2021-1490: Cisco Web Security Appliance Cross-Site Scripting Vulnerability

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-05-06 · updated 2026-06-17
Weakness: CWE-79

Description

A vulnerability in the web-based management interface of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface of an affected device. This vulnerability is due to improper validation of user-supplied input in the web-based management interface. An attacker could exploit this vulnerability by persuading a user to retrieve a crafted file that contains malicious payload and upload it to the affected device. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.

Affected products

Cisco Web Security Appliance (WSA): before 14.0 — fixed in 14.0

How to fix

Upgrade to a fixed version: Cisco Web Security Appliance (WSA) 14.0. Check the vendor advisory for mitigations.

References

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