Is CVE-2021-1490 being actively exploited?

CVE-2021-1490 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2021-1490?

CVE-2021-1490 has a CVSS 3.1 base score of 4.7 (MEDIUM).

CVE-2021-1490

MEDIUM · CVSS 4.7EPSS 0.7%EU EUVD

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.

Key facts

CVSS score: 4.7 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
EPSS score: 0.7% (52th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2021-6957)
Published: May 6, 2021
NVD last modified: June 17, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2021-6957 in the EU Vulnerability Database. Last updated in EUVD on November 8, 2024.

View on the EU Vulnerability Database

Affected products

cisco / web security appliance

Certified products that may be affected

2 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Cisco Web Security Appliance with AsyncOS 11.8 - Cisco Systems, Inc. - Common Criteria 567-LSS - active
Cisco Web Security Appliance 10.5 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-10799-2017 - archived

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wsa-xss-mVjOWchB(Vendor Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

Query CVEs from your AI assistant

The CVE/NVD Explorer brain answers CVE questions directly inside Claude, ChatGPT, or any MCP assistant — always up to date, no setup. Add it once and stop pasting advisories into chat.

Add the CVE brain