Detections
Analytics
Cisco IOS Software SNMPv3 Configuration Restriction (cisco-sa-snmpv3-qKEYvzsy)
medium Nessus Plugin ID 375169
Synopsis
The remote device is affected by a vulnerability.Description
According to its self-reported version and configuration, Cisco IOS Software is affected by a vulnerability.- A vulnerability in the implementation of the Simple Network Management Protocol Version 3 (SNMPv3) feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to poll an affected device using SNMP, even if the device is configured to deny SNMP traffic from an unauthorized source or the SNMPv3 username is removed from the configuration. This vulnerability exists because of the way that the SNMPv3 configuration is stored in the Cisco IOS Software and Cisco IOS XE Software startup configuration.
An attacker could exploit this vulnerability by polling an affected device from a source address that should have been denied. A successful exploit could allow the attacker to perform SNMP operations from a source that should be denied. Note: The attacker has no control of the SNMPv3 configuration. To exploit this vulnerability, the attacker must have valid SNMPv3 user credentials. (CVE-2025-20151)
The device is affected only if an SNMPv3 user has an access list attached and the stored configuration line for that user exceeds 255 characters. Cisco has not released a software update that addresses this vulnerability.
Please see the included Cisco BIDs and Cisco Security Advisory for more information.
Solution
Cisco has not released a fix for this vulnerability. Apply the workaround described in the vendor advisory: attach the access list to the SNMPv3 group instead of the user, or shorten the user, group, and access list names.See Also
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwi84832
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCwk87338
Plugin Details
Severity: Medium
ID: 375169
File Name: cisco-sa-snmpv3-qKEYvzsy-ios.nasl
Version: 1.2
Type: Combined
Family: CISCO
Published: 11/2/2026
Updated: 11/3/2026
Configuration: Enable paranoid mode
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Low
Score: 1.2
Percentile: 0.01
CVSS v2
Risk Factor: Medium
Base Score: 4
Temporal Score: 3
Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:N
CVSS Score Source: CVE-2025-20151
CVSS v3
Risk Factor: Medium
Base Score: 4.3
Temporal Score: 3.8
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:cisco:ios
Required KB Items: Settings/ParanoidReport, Host/Cisco/IOS/Version
Exploit Ease: No known exploits are available
Vulnerability Publication Date: 5/7/2025
Reference Information
CVE: CVE-2025-20151