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Vulnerability record · CVE-2026-20124 · published 5 August 2026

CVE-2026-20124: Cisco ios xe vulnerability

Cisco · Ios Xe

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.

7.7 CVSS 3.1 High EPSS 0.50% · top 59.6% CWE-772 · CWE-772
7.7CVSS 3.1 base score
0.50%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
1References
17 Sep 2026Last modified by NVD

Description

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-snmp-dos-ZAqNm4MD MitigationVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2023-20198Cisco IOS XE Web UI unauthenticated privilege escalation and implant deploymentCVE-2023-20198 is a critical flaw in the Cisco IOS XE web UI that lets an unauthenticated remote attacker gain initial access and create a local priv…KEVEPSS 100%analysed9.8CVE-2018-0151Cisco IOS/IOS XE QoS UDP Port 18999 Buffer OverflowCisco IOS and IOS XE contain a buffer overflow in the QoS subsystem caused by incorrect bounds checking of values in packets sent to UDP port 18999. …KEVEPSS 14%analysed9.8CVE-2017-3881Cisco IOS/IOS XE CMP Telnet Option Handling RCECisco IOS and IOS XE fail to restrict CMP-specific Telnet options to internal cluster communications and mishandle malformed CMP Telnet options, so a…KEVEPSS 99%analysed8.8CVE-2018-0167Cisco IOS, IOS XE and IOS XR LLDP buffer overflowMultiple buffer overflow flaws exist in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS, IOS XE and IOS XR Software. An unauthenticat…KEVEPSS 3.4%analysed8.8CVE-2017-6736Cisco IOS and IOS XE SNMP buffer overflow remote code executionThe SNMP subsystem in Cisco IOS and IOS XE contains a buffer overflow that can be triggered by a crafted SNMP packet sent over IPv4 or IPv6. It affec…KEVEPSS 70%analysed8.8CVE-2017-6737Cisco IOS and IOS XE SNMP Buffer Overflow RCECisco IOS and IOS XE contain a buffer overflow in the SNMP implementation that affects SNMPv1, v2c, and v3. An authenticated remote attacker who know…KEVEPSS 45%analysed8.8CVE-2017-6738Cisco IOS and IOS XE SNMP buffer overflow allows remote code executionThe SNMP subsystem in Cisco IOS and IOS XE Software contains a buffer overflow that affects SNMP versions 1, 2c, and 3. An authenticated remote attac…KEVEPSS 11%analysed8.8CVE-2017-6739Cisco IOS and IOS XE SNMP buffer overflow allows remote code executionCisco IOS and IOS XE contain a buffer overflow in the SNMP implementation that affects SNMP versions 1, 2c, and 3. A remote attacker who knows the SN…KEVEPSS 11%analysed

Source: NIST National Vulnerability Database (record CVE-2026-20124), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.