DoS in Cisco ISE RADIUS rejected-endpoint handling
CVE-2025-20343 is a high-severity denial-of-service vulnerability in Cisco Identity Services Engine (ISE). The issue is caused by a logic error in the RADIUS suppression feature associated with the setting "Reject RADIUS requests from clients with repeated failures." When Cisco ISE processes a RADIUS Access-Request for a MAC address that is already in the rejected endpoint state, it can mishandle a specific sequence of crafted requests and enter an unexpected state that causes the affected ISE node to restart. The vulnerable condition is only reachable when the suppression feature is enabled and the targeted MAC address has already been marked as rejected. Reported affected versions include Cisco ISE 3.4.0, 3.4 Patch 1, 3.4 Patch 2, and 3.4 Patch 3.
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Impact
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Exploits
No valid public exploits. Mallory filtered out 3 candidates as fakes, detection scripts, or README-only repos.
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Recent activity
11 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Cisco Identity Services Engine (ISE) logic error in handling certain RADIUS access requests that can be exploited remotely without authentication to trigger an unexpected restart (DoS).
A denial-of-service vulnerability in Cisco Identity Services Engine (ISE) caused by a logic error in the RADIUS suppression feature, allowing unauthenticated remote attackers to trigger system restarts via crafted RADIUS requests when the suppression setting is enabled.
High-severity unauthenticated remote denial-of-service in Cisco Identity Services Engine (ISE) due to a logic error in RADIUS request processing that can trigger unexpected restarts.
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Every observed campaign linking this CVE to a named adversary.
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Cross-references every affected SKU, including bundled OEM variants.
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