CVE-2026-20124 Cisco IOS XE Software SNMP Denial of Service Vulnerability

High 7.7 Published 5 Aug 2026 Updated 5 Aug 2026

An authenticated remote attacker can cause a Cisco IOS XE device to reload by sending a malformed SNMP request, resulting in a denial of service.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-20124?

CVE-2026-20124 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 5 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-772

Which versions are affected by CVE-2026-20124?

It affects 1 product.

Products include Cisco Ios Xe.

How do I fix CVE-2026-20124?

No fix has been published for CVE-2026-20124 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-20124 being exploited?

There is no known exploitation of CVE-2026-20124 in the wild and no public exploit code.

All Cisco Ios Xe vulnerabilities

Sources

Also known as GHSA-rxc8-wwjf-p7fp.