CVE-2026-20127
Cisco Catalyst SD-WAN Controller Authentication Bypass Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- cisco
Description
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.
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability.
- Added
- 25 Feb 2026
- Fix due (US federal)
- 27 Feb 2026
- Used by ransomware
- Not known
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By cisco
- 5 months later
· 5 months later
Published
Added to CISA KEV
Known exploited in the wild
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Analyzed | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 87.6% · top 0.2% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 10.0.
Weakness
Affected products
Cisco · Cisco Catalyst SD-WAN Manager
- affected 20.1.12
- affected 19.2.1
- affected 18.4.4
- affected 18.4.5
- affected 20.1.1.1
- affected 20.1.1
- affected 19.3.0
- affected 19.2.2
- affected 19.2.099
- affected 18.3.6
- affected 18.3.7
- affected 19.2.0
- affected 18.3.8
- affected 19.0.0
- affected 19.1.0
- affected 18.4.302
- affected 18.4.303
- affected 19.2.097
- affected 19.2.098
- affected 17.2.10
- affected 18.3.6.1
- affected 19.0.1a
- affected 18.2.0
- affected 18.4.3
- affected 18.4.1
- affected 17.2.8
- affected 18.3.3.1
- affected 18.4.0
- affected 18.3.1
- affected 17.2.6
- affected 17.2.9
- affected 18.3.4
- affected 17.2.5
- affected 18.3.1.1
- affected 18.3.5
- affected 18.4.0.1
- affected 18.3.3
- affected 17.2.7
- affected 17.2.4
- affected 18.3.0
- and 295 more
What to do
Exploitation: The Cisco PSIRT is aware of limited exploitation of this vulnerability. Cisco continues to strongly recommend that customers upgrade to a fixed software release to remediate this vulnerability.
References (2)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-20127)Record last updated .