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Advisory severityHigh8.6Cisco

High [CVE-2026-20352] Cisco Identity Services Engine RADIUS Denial of Service Vulnerability

This high-severity Cisco advisory covers CVE-2026-20352 affecting Identity Services Engine Software.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

cisco-sa-ise-RADIUS-dos-wR3hYPMw Source published Source updated

VulniPulse record published Record updated

CVE-2026-20352
Affected products & platforms
CiscoISEIdentity Services Engine
Open source advisory

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Summary

A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by sending a crafted RADIUS request directly to an affected device.

A successful exploit could allow the attacker to cause the ISE node to become unavailable. For single node deployments in that condition, endpoints that have not already authenticated would be unable to access the network until the node comes back up on its own.

Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of September 16, 2026, Security Advisories.

In addition, for further documentation of improvements and fixes in Cisco Identity Services Engine, see Cisco Identity Services Engine Security Hardening Release: September 2026.

Affected product named by the advisory: Identity Services Engine Software.

Affected versions
  • Scope: This vulnerability affects Cisco ISE Policy Service Nodes (PSNs) if they have RADIUS services enabled.
  • Release 3.2 (first fixed: 3.2 Patch 11)
  • Release 3.3 (first fixed: 3.3 Patch 12)
  • Release 3.4 (first fixed: 3.4 Patch 7)
  • Release 3.5 (first fixed: 3.5 Patch 4)

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Fixed versions
  • 3.2 Patch 11
  • 3.3 Patch 12
  • 3.4 Patch 7
  • 3.5 Patch 4

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation
  • Upgrade to the first fixed release for your train per the Fixed Releases table in this advisory.
  • Release 3.2: upgrade to 3.2 Patch 11.
  • Release 3.3: upgrade to 3.3 Patch 12.
  • Release 3.4: upgrade to 3.4 Patch 7.
  • Release 3.5: upgrade to 3.5 Patch 4.
Workaround status
  • There are no workarounds that address this vulnerability.

Official advisory · high-confidence parse· fetched 13 days ago·verify at source

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