Cisco Identity Services Engine Software: Incorrect Comparison
CVE-2025-20343 is a high-severity incorrect comparison vulnerability in Cisco Identity Services Engine Software from Cisco, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco Identity Services Engine Software versions: 3.4.0; 3.4 Patch 1; 3.4 Patch 2, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.71% chance of exploitation within 30 days, higher than 54% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Cisco Identity Services Engine Software you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Identity Services Engine Software | 3.4.0; 3.4 Patch 1; 3.4 Patch 2; 3.4 Patch 3 | Not stated |
| Cisco | Identity Services Engine | 3.4.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.6 | High | CNA (cisco.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A vulnerability in the RADIUS setting Reject RADIUS requests from clients with repeated failures on Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause Cisco ISE to restart unexpectedly. This vulnerability is due to a logic error when processing a RADIUS access request for a MAC address that is already a rejected endpoint. An attacker could exploit this vulnerability by sending a specific sequence of multiple crafted RADIUS access request messages to Cisco ISE. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when Cisco ISE restarts.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Comparison
The product compares two entities in a security-relevant context, but the comparison is incorrect.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco Identity Services Engine Software
- 10.0 Critical severity
- 7.6 High severity
- 7.2 High severity
- 8.6 High severity
- 7.1 High severity
- 9.1 Critical severity
Recent Incorrect Comparison vulnerabilities
- 9.8 Critical severity
- 9.4 Critical severity
- 8.1 High severity
- 7.5 High severity
- 8.8 High severity
- 7.2 High severity
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