CVE-2026-76504 (GCVE-0-2026-76504)
Vulnerability from cvelistv5 – Published: 2026-09-30 13:04 – Updated: 2026-09-30 19:58Title
Cisco Catalyst SD-WAN Manager System Account Authorization Bypass Vulnerability
Summary
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.
Severity
9.8 (Critical)
SSVC
Exploitation: active
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-30 17:40 UTC
CWE
- CWE-177 - Improper Handling of URL Encoding (Hex Encoding)
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://sec.cloudapps.cisco.com/security/center/c… | |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Cisco | Cisco Catalyst SD-WAN Manager |
Affected:
18.3.6
Affected: 18.3.7 Affected: 18.3.8 Affected: 17.2.10 Affected: 18.3.6.1 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 |
guessed |
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 27ff8fe2-2068-471e-a652-0f5b01af0d18
Exploited: Yes
Timestamps
First Seen: 2026-09-30
Asserted: 2026-09-30
Scope
Notes: Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability | Affected: Cisco / Catalyst SD-WAN Manager | 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. | Due date: 2026-10-03 | Known ransomware campaign use (KEV): Unknown | Notes (KEV): 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
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-177 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | Catalyst SD-WAN Manager |
| Due Date | 2026-10-03 |
| Date Added | 2026-09-30 |
| Vendorproject | Cisco |
| Vulnerabilityname | Cisco Catalyst SD-WAN Manager Hex Encoding Vulnerability |
| Knownransomwarecampaignuse | Unknown |
References
Created: 2026-09-30 18:00 UTC
| Updated: 2026-09-30 18:00 UTC
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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