What is CVE-2026-20128?
A vulnerability in the Data Collection Agent (DCA) feature of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to gain DCA user privileges on an affected system. This vulnerability is due to the presence of a credential file for the DCA user on an affected system. An attacker could exploit this vulnerability by sending a crafted HTTP request and reading the file that contains the DCA password from that affected system. A successful exploit could allow the attacker to access another affected system and gain DCA user privileges. Note: Cisco Catalyst SD-WAN Manager releases 20.18 and later are not affected by this vulnerability.
The record classifies CVE-2026-20128 under weakness class CWE-257. Its CVSS v3 base vector states that the flaw requires local access to the host, needs high-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 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
- 7.5 — HIGH
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 7.0% probability of exploitation in the next 30 days, higher than 94.0% 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-2026-20128 being exploited?
CISA added CVE-2026-20128 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-2026-20128 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-2026-20128
The record marks a vendor fix as available for CVE-2026-20128. 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-2026-20128 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-2026-20128
3 tracked threats in the Threadlinqs corpus reference CVE-2026-20128, 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
- 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, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on .