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.
The record classifies CVE-2026-20122 under weakness class CWE-648. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 245 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 5.4 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - EPSS (FIRST)
- 24.9% probability of exploitation in the next 30 days, higher than 97.8% of all scored CVEs
- CISA KEV
- Listed since 2026-03-04, federal remediation deadline 2026-04-23
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-02-25, last modified 2026-04-21
Is CVE-2026-20122 being exploited?
CISA added CVE-2026-20122 to the Known Exploited Vulnerabilities catalog on 2026-03-04, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-04-23 under BOD 22-01. Weaponised exploit code for CVE-2026-20122 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 47 in the Threadlinqs vulnerability feed.
- trickest/cve (trickest)
Affected products and versions
- Cisco: Catalyst Sd-wan Manager, Catalyst Sd-wan Manager 20.12.6
How to fix CVE-2026-20122
The record marks a vendor fix as available for CVE-2026-20122. Patch reference: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-vmanage-2026. Vendor advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-authbp-qwCX8D4v. Because CVE-2026-20122 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-04-23. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-20122
4 tracked threats in the Threadlinqs corpus reference CVE-2026-20122, either in the campaign’s CVE list or as an indicator on the campaign record.
- Cisco Catalyst SD-WAN Manager Zero-Day Exploitation Chain (CVE-2026-20245, CVE-2026-20127, CVE-2026-20182) — CRITICAL · 2026-07-02
- Cisco Catalyst SD-WAN CVE-2026-20182 — Critical Authentication Bypass Zero-Day Actively Exploited by UAT-8616 (CVSS 10.0, CISA KEV, ED 26-03) — CRITICAL · 2026-05-14
- CVE-2026-20127: Critical Cisco Catalyst SD-WAN Authentication Bypass Exploited by UAT-8616 Since 2023 (CVSS 10.0) — CRITICAL · 2026-03-16
- Cisco Catalyst SD-WAN Manager Active Exploitation — Arbitrary File Overwrite and Credential Exposure (CVE-2026-20122, CVE-2026-20128) — CRITICAL · 2026-03-06
Sources
Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.