# CVE-2026-20125: Denial of service in Cisco IOS XE Software

> An authenticated remote attacker can cause a Cisco IOS XE device to reload unexpectedly by sending malformed HTTP requests, 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:** 25 Mar 2026
- **Updated:** 25 Mar 2026
- **Also known as:** GHSA-qhwv-qr62-wrrh

## What is CVE-2026-20125?

CVE-2026-20125 is a high-severity denial of service vulnerability in Cisco IOS XE Software, published on 25 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE Software Release 3E could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition.

 This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malformed HTTP requests to an affected device. A successful exploit could allow the attacker to cause a watchdog timer to expire and the device to reload, resulting in a DoS condition. To exploit this vulnerability, the attacker must have a valid user account.

Weakness: CWE-228 (Improper Handling of Syntactically Invalid Structure)

## Which versions are affected by CVE-2026-20125?


## How do I fix CVE-2026-20125?

No fix has been published for CVE-2026-20125 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20125 being exploited?

There is no known exploitation of CVE-2026-20125 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-20125 and fix it if it is affected.

What it is: CVE-2026-20125 is a high-severity denial of service vulnerability in Cisco IOS XE Software, published on 25 Mar 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-2026-20125 in the wild and no public exploit code.

Affected product: Cisco IOS XE Software. 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-2026-20125/ (Markdown: https://insights.sbomify.com/CVE-2026-20125/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20125
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20125
- OSV: https://osv.dev/vulnerability/CVE-2026-20125

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-20125/
Summaries are generated and may contain mistakes; the official description above is the record.