The threat landscape surrounding enterprise networking infrastructure has escalated with the active exploitation of CVE-2026-20262, an arbitrary file write vulnerability affecting Cisco Catalyst SD-WAN Manager (formerly known as SD-WAN vManage). The security flaw allows an authenticated, remote attacker to bypass path restrictions, creating or overwriting arbitrary files on the underlying operating system. Because this flaw directly impacts the centralized management plane capable of orchestrating thousands of enterprise SD-WAN components, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added it to its Known Exploited Vulnerabilities (KEV) Catalog, signaling an immediate need for defensive mitigation and patching.
Severity: Moderate
Vulnerability Details
- Vulnerability Name: Cisco Catalyst SD-WAN Manager Arbitrary File Write Vulnerability
- CVE Identifier: CVE-2026-20262
- CVSS Score: 6.5
- Exploitation Status: Active, limited in-the-wild exploitation confirmed by Cisco PSIRT as of June 2026.
- Impact: Successful exploitation allows an authenticated attacker to write or overwrite arbitrary files on the underlying operating system, serving as a direct mechanism for root privilege escalation.
- Weakness Type: Improper Input Validation / Path Traversal (CWE-22) during the file upload process.
- Prerequisites: The attacker must possess valid credentials with at least lower-privileged, single-task user/write access.
Affected Products
This vulnerability affects all deployment types, including:
- On-Prem Deployment
- Cisco SD-WAN Cloud-Pro
- Cisco SD-WAN Cloud (Cisco Managed)
- Cisco SD-WAN for Government (FedRAMP)
Attack Chain & Iocs
- Stage 1 – Initial File Write (Path Traversal)
The attacker abuses the SdraAnyConnectFileUploadHandler to drop a WAR file outside the intended upload directory, using ../../../../ traversal into the WildFly deployments folder.
Log: vmanage-server.log
IOC: uploaded Remote Access Anyconnect profile file:
../../../../var/lib/wildfly/standalone/deployments/suspicious.war - Stage 2 – Malicious WAR Deployment
WildFly’s DeploymentScanner automatically picks up and deploys the dropped file, establishing a server-side foothold.
Log: vmanage-appserver.log
IOC: WFLYSRV0010: Deployed “suspicious.war” - Stage 3 – Webshell Interaction
The attacker interacts with the deployed webshell via HTTP POST, achieving remote code execution within the vManage environment.
Log: serviceproxy-access.log
IOC: POST /suspicious/index.jsp HTTP/1.1″ 200
Recommendations
- Prioritize patching internet-exposed SD-WAN Manager instances. These carry the highest risk given confirmed exploitation.
- If compromise is suspected, run request admin-tech on all control-plane components and engage Cisco TAC.
- Audit /var/log/nms/vmanage-server.log for path traversal patterns (../../../../) in upload handlers.
- Hunt for deployed WARs in /var/lib/wildfly/standalone/deployments/ that are not baseline-authorized.
- Review serviceproxy-access.log for anomalous POST requests to non-standard JSP paths.
Source:
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ
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