Threats / Cisco / CVE-2026-20127
CVE-2026-20127
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Cisco Catalyst SD-WAN Controller and Manager vulnerability
Authentication bypass in Cisco Catalyst SD-WAN Controller and Manager allows unauthenticated remote attackers to gain administrative privileges and manipulate SD-WAN fabric network configuration.
Verdict
Today item — known-exploited.
An unauthenticated remote attacker can bypass peering authentication via crafted requests, obtain high-privileged account access, and leverage NETCONF to alter SD-WAN fabric configuration, compromising network integrity and availability.
CISA KEV Yes · 2026-02-255EPSS 0.88243 (verify live)6Exploit Weaponized · public PoC7CVSS 103CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
18 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-02-25).
Probability (EPSS)
EPSS 0.88243 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 10 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) · Affected: Cisco, Catalyst SD-WAN Controller and Manager. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-287 Improper Authentication — weakness family: Authentication.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog the same day the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a public proof-of-concept / detection template). Catalog entries: Metasploit module. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I send crafted requests to the SD-WAN Controller or Manager to exploit the broken peering authentication mechanism.
Business
Network perimeter security is compromised as the authentication layer fails to validate legitimate access requests.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I bypass authentication checks and obtain login credentials for an internal, high-privileged non-root user account.
Business
Administrative access is granted to an unauthorized external party without credential compromise or social engineering.
3
Lateral reach — past segmentation narrative 3
Attacker
I access the NETCONF interface using the compromised high-privileged account to issue configuration commands.
Business
Attackers gain direct control over SD-WAN fabric network configuration and routing policies.
4
Data at risk — exfiltration narrative 4
Attacker
I manipulate network configuration to redirect traffic, isolate segments, or degrade SD-WAN performance.
Business
Network availability and data integrity are compromised; business operations dependent on SD-WAN connectivity are disrupted.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05