CVE-2026-20127: Cisco Catalyst SD-WAN Controller and Manager

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Cisco Catalyst SD-WAN Controller and Manager. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-02-25, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-02-27; treat that as the outer limit, not the target.
EPSS 88.5%, percentile 99.8: FIRST’s model estimates a 88.5% chance of exploitation activity in the next 30 days, higher than 99.8% of all scored CVEs (very high). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Editorial verdict: Act now. Cisco SD-WAN CVE-2026-20127: CVSS 10 Bypass, ED 26-03 — If you run on-prem Catalyst SD-WAN control components, upgrade and hunt now: a sophisticated actor has used this bypass for years, and the follow-on SD-WAN bugs CISA keeps adding to KEV show the platform is still being targeted.

What it is

A vulnerability in the peering authentication in Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, and Cisco Catalyst SD-WAN Validator, formerly SD-WAN vBond, could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric. 

CISA’s summary

Cisco Catalyst SD-WAN Controller, formerly SD-WAN vSmart, and Cisco Catalyst SD-WAN Manager, formerly SD-WAN vManage, contain an authentication bypass vulnerability could allow an unauthenticated, remote attacker to bypass authentication and obtain administrative privileges on an affected system. This vulnerability exists because the peering authentication mechanism in an affected system is not working properly. An attacker could exploit this vulnerability by sending crafted requests to an affected system. A successful exploit could allow the attacker to log in to an affected Cisco Catalyst SD-WAN Controller as an internal, high-privileged, non-root user account. Using this account, the attacker could access NETCONF, which would then allow the attacker to manipulate network configuration for the SD-WAN fabric.

Weakness type: CWE-287.

Product: Cisco Catalyst SD-WAN Controller and Manager · Assigned by: cisco · Published: 2026-02-25

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
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

Severity scores

Scored by	CVSS	Score	Vector
cisco	3.1	10 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Privileges required: none (no login)
User interaction: none
Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2026-02-25; federal due date 2026-02-27. Known ransomware use: Unknown.
CISA required action: Please adhere to CISA’s guidelines to assess exposure and mitigate risks associated with Cisco SD-WAN devices as outlines in CISA’s Emergency Directive 26-03 (URL listed below in Notes) and CISA’s “Hunt & Hardening Guidance for Cisco SD-WAN Devices (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 88.48% probability of exploitation activity in the next 30 days; percentile 99.8.

Timeline

2026-02-25 — Added to CISA’s Known Exploited Vulnerabilities catalog
2026-02-25 — CVE record published by cisco
2026-02-25 — erroneo.us brief: Cisco SD-WAN CVE-2026-20127: CVSS 10 Bypass, ED 26-03
2026-02-27 — CISA remediation deadline for US federal agencies
2026-06-16 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.