Actively Exploited — CISA KEV

CVE-2026-20122: Cisco Catalyst SD-WAN Manger Vulnerability

Severity: Medium | CVSS 3.1: 5.4 | Published: 2026-02-25 | KEV Added: 2026-04-20

What is CVE-2026-20122?

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.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-648.

Attack Vector Breakdown

  • Attack Vector: Network
  • Attack Complexity: Low
  • Privileges Required: Low
  • User Interaction: None
  • Scope: Unchanged
  • Confidentiality: Low
  • Integrity: Low
  • Availability: None

Impact Analysis

This vulnerability is exploitable over the network, meaning any system reachable via the internet or internal network is potentially at risk without physical access. The attack complexity is low, meaning exploitation does not depend on specialized conditions or race windows.

Exploitation Probability (EPSS): 1.3% chance of exploitation in the next 30 days (80th percentile). While the base probability may appear low, inclusion in CISA KEV confirms real-world exploitation is already occurring.

Is CVE-2026-20122 being exploited?

Yes. CVE-2026-20122 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2026-04-20. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2026-04-23.

How to fix CVE-2026-20122

Download the fixed software release from the Cisco Software Center. For IOS/IOS XE, use the Cisco Software Checker to identify the specific fixed release. If upgrading is not immediately possible, apply the workaround or mitigation described in the Cisco Security Advisory (e.g. ACLs, disabling affected features). Check the Cisco Security Advisories page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Catalyst SD-WAN Manger or sharing the same weakness (CWE-648):

  • CVE-2026-20182 (Critical 10.0) [same vendor] — May 2026: This security advisory provides the details and fix information for…
  • CVE-2026-20133 (Medium 6.5) [same vendor] — A vulnerability in Cisco Catalyst SD-WAN Software could allow an…
  • CVE-2026-20128 (High 7.5) [same vendor] — A vulnerability in the Data Collection Agent (DCA) feature of Cisco Catalyst…
  • CVE-2026-20131 (Critical 10.0) [same vendor] — A vulnerability in the web-based management interface of Cisco Secure Firewall…
  • CVE-2022-20775 (High 7.8) [same vendor] — A vulnerability in the CLI of Cisco SD-WAN Software could allow an…

Frequently asked questions

Is CVE-2026-20122 critical?

CVE-2026-20122 has a CVSS 3.1 base score of 5.4 — Medium severity. Prioritize based on exposure and the active exploitation signal from the KEV listing.

Is CVE-2026-20122 being actively exploited?

Yes — CISA added CVE-2026-20122 to the Known Exploited Vulnerabilities catalog on 2026-04-20. Inclusion in KEV means CISA has confirmed in-the-wild exploitation.

How do I patch CVE-2026-20122?

Apply the security update from Cisco for Catalyst SD-WAN Manger. Federal agencies must remediate by 2026-04-23 under BOD 22-01. Refer to the Cisco Security Advisories for the official patch.

What type of vulnerability is CVE-2026-20122?

CVE-2026-20122 is classified under CWE-648.

What is the CVSS score for CVE-2026-20122?

CVE-2026-20122 has a CVSS 3.1 base score of 5.4, classifying it as Medium severity. The attack vector is Network, attack complexity is Low, and non-zero privileges are required.