Cisco has released security updates for a medium-severity security flaw in Catalyst SD-WAN Manager that has come under active exploitation in the wild.
The vulnerability, tracked as CVE-2026-20262, carries a CVSS score of 6.5 out of 10.0.
"A vulnerability in the web UI of Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, could allow an authenticated, remote attacker to create a file or overwrite any file on the filesystem of an affected system," Cisco said in an advisory.
The issue, the networking equipment company added, stems from inadequate validation of user-supplied input during a file upload process. An attacker could exploit this behavior to create or overwrite any file on the underlying operating system by sending crafted HTTP requests to an affected API endpoint.
This, in turn, could be weaponized to elevate to the root. However, successful exploitation hinges on the attacker already having valid credentials with at least write access.
The vulnerability impacts the following products regardless of the deployment type -
- Cisco Catalyst SD-WAN Manager On-Prem
- Cisco SD-WAN Cloud-Pro
- Cisco SD-WAN Cloud (Cisco Managed)
- Cisco SD-WAN for Government (FedRAMP)
Patches have been released to address the issue -
- Cisco Catalyst SD-WAN Release 20.9.9.1 and earlier - Fixed in 20.9.9.2
- Cisco Catalyst SD-WAN Release 20.12.7.1 and earlier - Fixed in 20.12.7.2
- Cisco Catalyst SD-WAN Release 20.15.4.4 and earlier - Fixed in 20.15.4.5
- Cisco Catalyst SD-WAN Release 20.15.5.2 and earlier - Fixed in 20.15.5.3
- Cisco Catalyst SD-WAN Release 20.18.3 - Fixed in 20.18.3.1
- Cisco Catalyst SD-WAN Release 26.1.1.1 and earlier - Fixed in 26.1.1.2
Cisco said it "became aware of limited exploitation of this vulnerability" in June 2026, adding it was discovered during internal security testing.
The company has also shared indicators of compromise associated with the malicious activity, urging customers to audit "/var/log/nms/vmanage-server.log" for suspicious WAR file uploads as below -
11-June-2026 03:53:37,310 EDT INFO [a66cdc5f-807d-4c23-944e-5c809a2ece6b] [server] [SdraAnyConnectFileUploadHandler] (default task-40704) |default| uploaded Remote Access Anyconnect profile file: ../../../../var/lib/wildfly/standalone/deployments/suspicious.war to vManage.
Other indicators include attempts to deploy malicious code and interact with it, although Cisco has warned that they may not "consistently appear" in every incident log. The follow-on activities related to this vulnerability are -
- /var/log/nms/vmanage-appserver.log: 11-June-2026 07:52:55,275 UTC INFO [server] (DeploymentScanner-threads - 2) WFLYSRV0010: Deployed "suspicious.war" (runtime-name : "suspicious.war")
- /var/log/nms/containers/service-proxy/serviceproxy-access.log: [2026-06-11T07:57:33.635Z] "POST /suspicious/index.jsp HTTP/1.1" 200 - 267 76 17 - "1.1.1.54" "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:84.0) Gecko/20100101 Firefox/84.0" "d7336b83-422b-4000-93e1-0296f102bbed" "1.1.1.4:8443" "127.0.0.1:8080"
CVE-2026-20262 is the eighth security flaw impacting Cisco SD-WAN to be flagged as actively exploited this year alone after CVE-2026-20245, CVE-2026-20182, CVE-2026-20127, CVE-2026-20122, CVE-2026-20128, CVE-2026-20133, and CVE-2022-20775. The exploitation of some of these flaws has been attributed to an advanced persistent threat (APT) actor named UAT-8616.
The development has prompted the U.S. Cybersecurity and Infrastructure Security Agency (CISA) to add the flaw to its Known Exploited Vulnerabilities (KEV) catalog, requiring Federal Civilian Executive Branch (FCEB) agencies to apply the fixes by June 29, 2026.
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