CVE-2021-1359: Cisco Web Security Appliance Privilege Escalation Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-08 · updated 2026-06-17
Weakness: CWE-112

Description

A vulnerability in the configuration management of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an authenticated, remote attacker to perform command injection and elevate privileges to root. This vulnerability is due to insufficient validation of user-supplied XML input for the web interface. An attacker could exploit this vulnerability by uploading crafted XML configuration files that contain scripting code to a vulnerable device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system and elevate privileges to root. An attacker would need a valid user account with the rights to upload configuration files to exploit this vulnerability.

Affected products

Cisco Asyncos: from 11.8.0 before 12.0.3-005; from 12.5.0 before 12.5.2 — fixed in 12.0.3-005, 12.5.2
Cisco Web Security Appliance (WSA): 11.8.0-429, 11.8.0-453

How to fix

Upgrade to a fixed version: Cisco Asyncos 12.0.3-005, 12.5.2. Check the vendor advisory for mitigations.

References

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