CVE-2026-20245
Published: 04 June 2026
Summary
CVE-2026-20245 is a high-severity Improper Encoding or Escaping of Output (CWE-116) vulnerability in Cisco Catalyst Sd-Wan Manager. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Network Device CLI (T1059.008); ranked in the top 5.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and AC-3 (Access Enforcement).
Deeper analysis
A vulnerability in the CLI of Cisco Catalyst SD-WAN Controller (formerly vSmart), Cisco Catalyst SD-WAN Manager (formerly vManage), and Cisco Catalyst SD-WAN Validator (formerly vBond) allows an authenticated local attacker to execute arbitrary commands as root. The issue stems from insufficient validation of user-supplied input, enabling command injection when a crafted file is uploaded to the affected system. It carries a CVSS 3.1 score of 7.8 and is tracked under CWE-116.
An attacker must possess netadmin privileges, which can be obtained through valid credentials or by chaining with other vulnerabilities, to exploit the flaw and achieve root-level command execution. Cisco has observed limited instances of successful exploitation that resulted in configuration changes being pushed to edge devices, though the vendor states it is not aware of exploitation via other methods.
The Cisco Security Advisory published on May 14, 2026, recommends upgrading to the fixed software releases and verifying the configuration of edge devices. The vulnerability is also referenced in the CISA Known Exploited Vulnerabilities catalog.
The current EPSS score stands at 0.0033.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-34341
Vulnerability details
A vulnerability in the CLI of Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, could allow an authenticated, local attacker to execute arbitrary commands as root…
more
by supplying a crafted file to the affected system. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by uploading a crafted file to the affected system. A successful exploit could allow the attacker to perform command injection attacks on an affected system and elevate their privileges as the root user. To exploit this vulnerability, the attacker must have netadmin privileges on the affected system. This would require valid credentials or exploitation of or . Cisco is not aware of successful exploitation by other methods. Cisco has observed limited cases where the exploitation of this bug resulted in a configuration change pushed to edge devices. Cisco recommends that customers upgrade to the fixed software that is documented in the that was published on May 14, 2026, and verify the configuration of the edge devices.
- CWE(s)
- KEV Date Added
- 09 June 2026
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct CLI command injection on network devices enables T1059.008 for root-level arbitrary command execution.
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of user-supplied input (the crafted file) to block the command-injection vector that leads to root execution.
Enforces least-privilege restrictions so that even a netadmin account cannot reach root-level command execution paths.
Enforces access-control policy on CLI operations, limiting the ability of an authenticated user to perform the unauthorized file-triggered actions.