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Cisco Catalyst SD-WAN Manager Arbitrary File Write Vulnerability

mediumknown exploitedpublic exploitCVE-2026-20262
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
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. This vulnerability exists because the affected software does not properly validate user-supplied input during a file upload process. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected API endpoint of the affected system. A successful exploit could allow the attacker to create or overwrite any file on the underlying operating system. This file could later be used to elevate to root . To exploit this vulnerability, the attacker must have valid credentials with at least write access. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ Security Impact Rating: Medium CVE: CVE-2026-20262

CSIRTS triage

What
The vulnerability allows an authenticated, remote attacker to create or overwrite any file on the filesystem of an affected system.
Who is affected
Authenticated users with write access to Cisco Catalyst SD-WAN Manager.
Urgency
Remediation is important as the vulnerability is actively exploited and has medium severity.
Action
Update to the latest software version released by Cisco.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source
Cisco Security Advisories (INTL · vendor-psirt · site)
Severity
medium
Published
2026-06-15
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ?vs_f=Cisco%20Security%20Advisory%26vs_cat=Security%20Intelligence%26vs_type=RSS%26vs_p=Cisco%20Catalyst%20SD-WAN%20Manager%20Arbitrary%20File%20Write%20Vulnerability%26vs_k=1

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-20262coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Cisco Catalyst SD-WAN

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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