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Known Exploited Vulnerability
9.8
CRITICAL CVSS 3.1
CVE-2026-76504
Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability - [Actively Exploited]
Overview
Description

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.

Details
INFO

Published Date :

Sept. 30, 2026, 1:17 p.m.

Last Modified :

Oct. 3, 2026, 12:16 a.m.

Remotely Exploit :

Yes !

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

Cisco Catalyst SD-WAN Manager contains a hex encoding vulnerability that could allow an unauthenticated, remote attacker to access an affected system with privileges of the admin user due to improper handling of URI encoding in an HTTP request.

Required Action :

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Known Ransomware Campaign Use:

Unknown

Notes :

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU ; ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-76504

Impact
Affected Products

The following products are affected by CVE-2026-76504 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco catalyst_sd-wan_manager
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 CRITICAL [email protected]
Solution
Apply vendor patches to address improper URI encoding and authentication bypass.
  • Apply Cisco security patches for Catalyst SD-WAN Manager.
  • Update the product to the latest secure version.
  • Restrict access to API endpoints.
  • Monitor API traffic for suspicious requests.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-76504.

URL Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU Mitigation Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76504 US Government Resource
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-76504 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-76504 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-76504 vulnerability anywhere in the article.

  • TheCyberThrone
Microsoft Releases Out-of-Band Exchange Security Update

October 6, 2026Executive SummaryMicrosoft has released an out-of-band security update for Exchange Server to address CVE-2026-96940, an Elevation of Privilege vulnerability that could allow an authent ... Read more

Published Date: Oct 06, 2026 (2 weeks ago)
  • TheCyberThrone
CVE-2026-90970: Critical GitLab AI Gateway Vulnerability

October 3, 2026AI infrastructure is quickly becoming part of the enterprise attack surface, and CVE-2026-90970 is a good example of why.Zero-Day Vulnerability ReportsThe vulnerability affects GitLab A ... Read more

Published Date: Oct 03, 2026 (2 weeks, 3 days ago)
  • TheCyberThrone
FortiMail Zero-Day Exploited in the Wild — CVE-2026-104286

October 2, 2026Executive SummaryFortinet has confirmed active exploitation of a critical FortiMail zero-day, CVE-2026-104286. The vulnerability carries a CVSS score of 9.8 and can allow an unauthentic ... Read more

Published Date: Oct 02, 2026 (2 weeks, 4 days ago)
  • The Hacker News
Critical FortiMail Zero-Day Flaw Exploited in Attacks Allows Unauthenticated Arbitrary File Writes

The U.S. Cybersecurity and Infrastructure Security Agency (CISA), on Thursday, added a critical security flaw impacting Fortinet FortiMail to its Known Exploited Vulnerabilities (KEV) catalog, followi ... Read more

Published Date: Oct 02, 2026 (2 weeks, 4 days ago)
  • TheCyberThrone
CVE-2026-76504: Cisco SD-WAN Manager Zero-Day Exploited in Wild

October 1, 2026Executive SummaryCisco Catalyst SD-WAN Manager is dealing with a serious zero-day that is already being exploited in the wild.Hacking & CrackingTracked as CVE-2026-76504, the flaw allow ... Read more

Published Date: Oct 01, 2026 (2 weeks, 5 days ago)
  • The Hacker News
CISA Adds Exploited Cisco Catalyst SD-WAN Manager Auth Bypass to KEV

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Wednesday added a critical authentication bypass flaw impacting Cisco Catalyst SD-WAN Manager to its Known Exploited Vulnerabilities ... Read more

Published Date: Oct 01, 2026 (2 weeks, 5 days ago)
  • The Hacker News
Cisco Warns of Attackers Exploiting Critical Authentication Bypass in SD-WAN Manager

Attackers are exploiting a new critical zero-day 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 f ... Read more

Published Date: Sep 30, 2026 (2 weeks, 6 days ago)
  • security.nl
Cisco waarschuwt voor misbruik van kritiek lek in Catalyst SD-WAN Manager

Cisco waarschuwt organisaties voor actief misbruik van een kritieke kwetsbaarheid in de Cisco Catalyst SD-WAN Manager en heeft vandaag beveiligingsupdates uitgebracht om het probleem te verhelpen. De ... Read more

Published Date: Sep 30, 2026 (2 weeks, 6 days ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-76504 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Oct. 03, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/76xxx/CVE-2026-76504.json">CVE-2026-76504</a>
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 01, 2026

    Action Type Old Value New Value
    Removed SSVC {'id': 'CVE-2026-76504', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-30T17:40:04.037537Z'}
    Added SSVC {'id': 'CVE-2026-76504', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-30T00:00:00+00:00'}
  • Initial Analysis by [email protected]

    Sep. 30, 2026

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:* versions up to (excluding) 20.9.10.1 *cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:* versions from (including) 20.12 up to (excluding) 20.12.8.2 *cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:* versions from (including) 20.15 up to (excluding) 20.15.6.1 *cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:* versions from (including) 20.18 up to (excluding) 20.18.4.1 *cpe:2.3:a:cisco:catalyst_sd-wan_manager:*:*:*:*:*:*:*:* versions from (including) 26.1 up to (excluding) 26.1.2.1 *cpe:2.3:a:cisco:catalyst_sd-wan_manager:26.2:*:*:*:*:*:*:*
    Added Reference Type Cisco Systems, Inc.: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU Types: Mitigation, Vendor Advisory
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76504 Types: US Government Resource
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Sep. 30, 2026

    Action Type Old Value New Value
    Added Date Added 2026-09-30
    Added Due Date 2026-09-30
    Added Required Action 2026-09-30
    Added Vulnerability Name 2026-09-30
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 30, 2026

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76504
    Added SSVC {'id': 'CVE-2026-76504', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'active'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-09-30T17:40:04.037537Z'}
  • New CVE Received by [email protected]

    Sep. 30, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    Added CWE CWE-177
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/76xxx/CVE-2026-76504.json">CVE-2026-76504</a>
    Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-webauth-xr8beuuU
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact