How severe is CVE-2026-20127?

CVE-2026-20127 has a CVSS score of 10/10, rated CRITICAL. Immediate patching is strongly recommended.

Which products are affected by CVE-2026-20127?

Affected package information for CVE-2026-20127 is not yet fully mapped. Check the official advisory links for details.

How do I patch CVE-2026-20127?

Apply the cisco catalyst sd-wan manager security patch or hotfix for CVE-2026-20127 on the affected version, following the vendor advisory for your exact build.

How do I detect CVE-2026-20127 across my infrastructure?

Inventory every cisco catalyst sd-wan manager deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.

How do I mitigate CVE-2026-20127 if there is no patch (or I can't update yet)?

Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.

How does O3 Security protect against CVE-2026-20127?

O3 detects and blocks CVE-2026-20127 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Is CVE-2026-20127 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-20127 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-20127?

CVE-2026-20127 has an EPSS (Exploit Prediction Scoring System) score of 88.2%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2026-20127 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2026-20127 (Cisco Catalyst SD-WAN Controller and Manager Authentication Bypass Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2026-02-25. CISA required all US federal civilian agencies to remediate this vulnerability by 2026-02-27. The required action was: 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. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2026-20127?

CVE-2026-20127 is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2026-20127?

CVE-2026-20127 affects cisco catalyst sd-wan manager (1 version, e.g. 20.12.6); cisco sd-wan vbond orchestrator (1 version, e.g. 20.12.6); cisco sd-wan vsmart controller (1 version, e.g. 20.12.6). Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2026-20127?

2 Metasploit modules reference CVE-2026-20127, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-20127 published, and has it been updated?

CVE-2026-20127 was published on February 25, 2026 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-20127: Catalyst Sd-Wan Manager Improper Authentication…

EPSS Exploitation Probability

via FIRST.org ↗

88.2%probability of exploitation in next 30 days

Very High Risk100th percentile+30.45%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Affected Products

3 products · 15 configurations

Application

catalyst sd-wan managercisco

≥ 20.16 && < 20.18.2.1

1 version

20.12.6

Application

sd-wan vbond orchestratorcisco

≥ 20.16 && < 20.18.2.1

1 version

20.12.6

Application

sd-wan vsmart controllercisco

≥ 20.16 && < 20.18.2.1

1 version

20.12.6

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every cisco catalyst sd-wan manager deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for exploitation at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the cisco catalyst sd-wan manager security patch or hotfix for CVE-2026-20127 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2026-20127 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.

Tailored to CVE-2026-20127. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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

O3 Security · Runtime Protection

Is CVE-2026-20127 being exploited in your environment?

O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2026-20127 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.

Protect my workloads How runtime protection works

CVE-2026-20127

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

How O3 protects you

Frequently Asked Questions

Is CVE-2026-20127 being exploited in your environment?