Cisco Secure Client: Improper Verification of Cryptographic Signature
CVE-2025-20206 is a high-severity improper verification of cryptographic signature vulnerability in Cisco Secure Client from Cisco, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected Cisco Secure Client versions: 4.9.00086; 4.9.01095; 4.9.02028, 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 0.18% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Secure Client to 5.1.8.105 or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Secure Client | 4.9.00086; 4.9.01095; 4.9.02028; 4.9.03047; 4.9.03049; 4.9.04043; 4.9.04053; 4.9.05042; and 32 more ranges | Not stated |
| Cisco | Secure Client | before 5.1.8.105 | 5.1.8.105 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.1 | High | CNA (cisco.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A vulnerability in the interprocess communication (IPC) channel of Cisco Secure Client for Windows could allow an authenticated, local attacker to perform a DLL hijacking attack on an affected device if the Secure Firewall Posture Engine, formerly HostScan, is installed on Cisco Secure Client. This vulnerability is due to insufficient validation of resources that are loaded by the application at run time. An attacker could exploit this vulnerability by sending a crafted IPC message to a specific Cisco Secure Client process. A successful exploit could allow the attacker to execute arbitrary code on the affected machine with SYSTEM privileges. To exploit this vulnerability, the attacker must have valid user credentials on the Windows system.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco Secure Client
- 7.3 High severity
- 8.2 High severity
- 7.8 High severity
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 9.8 Critical severity
- 9.3 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 9.3 Critical severity
- 8.8 High severity
Spotted an error? Tell us.