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CVE-2025-20343VulnerabilityPublished

Cisco Identity Services Engine RADIUS Suppression Denial of Service Vulnerability

Affects CiscoSource GCVE Database

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Authoritative record:CVE-2025-20343· High 8.6

Not known to be exploited · CVSS 8.6 High.

Data as of 4 Nov 2026, 18:07 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Nov 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.

What to do

AI-suggested

Users should verify the configuration of the 'Reject RADIUS requests from clients with repeated failures' setting in Cisco ISE under Administration > System > Settings > Protocols > RADIUS. Adjusting or disabling this setting may mitigate the risk. Monitor Cisco advisories for official patches or updates addressing this vulnerability.

Description

A denial of service vulnerability exists in Cisco Identity Services Engine (ISE) versions 3.4.0 through 3.4 Patch 3 when the default setting to reject RADIUS requests from clients with repeated failures is enabled. This setting, enabled by default, can be found under RADIUS protocol settings in the Cisco ISE web UI. The vulnerability could allow an attacker to cause service disruption by exploiting the suppression of repeated failed RADIUS client requests.

References

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