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

> 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.

- **Severity:** High 7.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 5 Aug 2026
- **Updated:** 5 Aug 2026
- **Also known as:** GHSA-rxc8-wwjf-p7fp

## 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 (Missing Release of Resource after Effective Lifetime)

## Which versions are affected by CVE-2026-20124?

It affects 1 product.


Products: 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.

## Is CVE-2026-20124 being exploited?

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

## Other vulnerabilities in Cisco Ios Xe

- [CVE-2023-20198](https://insights.sbomify.com/CVE-2023-20198/): Cisco IOS XE Web UI Privilege Escalation (critical 10.0, exploited in the wild)
- [CVE-2018-0151](https://insights.sbomify.com/CVE-2018-0151/): Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-20273](https://insights.sbomify.com/CVE-2023-20273/): Cisco IOS XE Web UI Command Injection (high 7.2, exploited in the wild)
- [CVE-2025-20188](https://insights.sbomify.com/CVE-2025-20188/): Hardcoded credentials in Cisco IOS XE Software (critical 10.0)
- [CVE-2021-34770](https://insights.sbomify.com/CVE-2021-34770/): Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20124 and fix it if it is affected.

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

Affected product: Cisco Ios Xe. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-20124/ (Markdown: https://insights.sbomify.com/CVE-2026-20124/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20124
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20124
- OSV: https://osv.dev/vulnerability/CVE-2026-20124

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20124/
Summaries are generated and may contain mistakes; the official description above is the record.