Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2026-76504

Cisco Catalyst SD-WAN Manager

Cisco / Cisco Catalyst SD-WAN Manager · 18.3.6

View live feed Monitor via API Watch CVE-2026-76504
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
—
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-76504 is an unauthenticated vulnerability affecting Cisco Cisco Catalyst SD-WAN Manager. A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Cisco / Cisco Catalyst SD-WAN Manager 18.3.6.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Cisco Catalyst SD-WAN Manager

A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint.

An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass authentication and gain access to the API as the admin user.

Cisco Affected
Cisco Catalyst SD-WAN Manager
18.3.6 18.3.7 18.3.8 17.2.10 18.3.6.1 18.2.0 18.4.3 18.4.1 17.2.8 18.3.3.1 18.4.0 18.3.1 17.2.6 17.2.9 18.3.4 17.2.5 18.3.1.1 18.3.5 18.4.0.1 18.3.3 17.2.7 17.2.4 18.3.0
Published
30 Sep 2026
Exploitation Reported
30 Sep 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

edge cisa

CVE References

  • CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-76504
  • cisco-sa-sdwan-webauth-xr8beuuU sec.cloudapps.cisco.com · CVE Record https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurity...

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

Cisco PSIRT CSAF

Recorded 30 Sep 2026

A trusted third party reported exploitation.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Cisco PSIRT CSAF First 2026-09-30 13:49 UTC
Rapid7 2026-09-30 15:21 UTC
The Hacker News 2026-09-30 15:30 UTC
CISA 2026-09-30 17:31 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

—

Weaknesses

Improper Handling of URL Encoding (Hex Encoding) CWE-177

Recent mention · Rapid7

Critical Cisco Catalyst SD-WAN Manager API authentication bypass exploited in the wild (CVE-2026-76504)

OverviewOn September 30, 2026, Cisco published a security advisory for CVE-2026-76504, a critical API authentication bypass vulnerability affecting Cisco Catalyst SD-WAN Manager. The vulnerability has a CVSSv3.1 score of 9.8 and results from improper handling of URL encoding...

Read full advisory

All Mentions

Recent mention · Rapid7

Critical Cisco Catalyst SD-WAN Manager API authentication bypass exploited in the wild (CVE-2026-76504)

Rapid7 · 30 Sep 2026

OverviewOn September 30, 2026, Cisco published a security advisory for CVE-2026-76504, a critical API authentication bypass vulnerability affecting Cisco Catalyst SD-WAN Manager. The vulnerability has a CVSSv3.1 score of 9.8 and results from improper handling of URL encoding (CWE-177). An unauthenticated, remote attacker can send a crafted HTTP request that bypasses an authentication rule for a specific API endpoint, gaining access to the API with the privileges of the admin user.According to Cisco, CVE-2026-76504 is being actively exploited in the wild; Cisco PSIRT became aware of the...

Recent mention · Cisco Security Advisory

Cisco Catalyst SD-WAN Manager API Authentication Bypass Vulnerability

Cisco Security Advisory · 30 Sep 2026

A vulnerability in the API session-based authentication management of Cisco Catalyst SD-WAN Manager could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user. This vulnerability is due to improper handling of URI encoding in an HTTP request, which allows the request to bypass an authentication rule that is intended to restrict access to a specific API endpoint. An attacker could exploit this vulnerability by sending a crafted HTTP request to the API of the affected system. A successful exploit could allow the attacker to bypass...

Recent mention · The Hacker News

Cisco Warns of Attackers Exploiting Critical Authentication Bypass in SD-WAN Manager

The Hacker News · 30 Sep 2026

Swati KhandelwalSep 30, 2026Vulnerability / Network Security Attackers are exploiting a critical flaw in Cisco Catalyst SD-WAN Manager, the system companies use to manage their Cisco SD-WAN networks, Cisco said in an advisory on September 30. The flaw, CVE-2026-76504, could allow a remote attacker with no login access to use the Manager's API as the admin user. Fixed releases are available, and there is no workaround. CVE-2026-76504 carries a CVSS score of 9.8 out of 10. It sits in the part of the Manager's API that handles login sessions. The Manager mishandles URI encoding in an HTTP...

Timeline

From disclosure to observed exploitation

  1. 17:31 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 15:30 UTC

    KEV confirmed by The Hacker News

    Exploitation attested by an external source

  3. 15:21 UTC

    KEV confirmed by Rapid7

    Exploitation attested by an external source

  4. 13:49 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  5. 13:20 UTC

    Added to the Previdian watchlist

    Pro and Enterprise Watch users had 4 hours of early warning before CISA KEV. Also 1 hour before Previdian confirmed it as a KEV.

  6. 13:04 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 12:02 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
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  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-76504

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2026-76504",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": null,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}