CVE intelligence and bounded remediation

CVE-2021-1359 — Cisco Web Security Appliance security vulnerability

High CVSS 9

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.

Severity
High
CVSS
9 (2.0)
Published
2021-07-08
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-112

Affected products

  • cisco / web_security_appliance / 11.8.0-429
  • cisco / web_security_appliance / 11.8.0-453
  • cisco / asyncos

Showing 3 representative product identities from 4 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Command, code, expression, and template injection

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Check exposure

  • Trace untrusted values to process execution, interpreters, evaluators, template engines, dynamic imports, and administrative scripting features.
  • Determine whether the affected path is reachable across each trust boundary and which service account or host privilege it inherits.
  • Review configuration for optional execution features, unsafe compatibility modes, and shell invocation.

Remediate safely

  • Replace string-built commands or evaluated code with fixed operations and structured argument APIs that do not invoke a shell.
  • Use strict allowlists for operation identifiers and reject unexpected input before it reaches any interpreter.
  • Update the affected component and add inert regression tests covering metacharacters, encoding variants, and alternate request paths.

Authoritative sources

Complete CVE record and remediation plan

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