# CVE-2022-20758: Cisco IOS XR Software Border Gateway Protocol Ethernet VPN Denial of Service Vulnerability

> Remote attackers with valid BGP peer access can cause a denial of service by sending malicious EVPN update messages to Cisco IOS XR devices.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Apr 2022
- **Updated:** 6 Nov 2024
- **Also known as:** GHSA-786f-rrh2-r2pf

## What is CVE-2022-20758?

CVE-2022-20758 is a medium-severity denial of service vulnerability in Cisco Ios Xr, published on 15 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer.

Weakness: CWE-399

## Which versions are affected by CVE-2022-20758?

It affects 1 product.


Products: Cisco Ios Xr.

## How do I fix CVE-2022-20758?

No fix has been published for CVE-2022-20758 yet. Limit exposure of the affected software until one is available.

## Is CVE-2022-20758 being exploited?

There is no known exploitation of CVE-2022-20758 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xr

- [CVE-2020-3118](https://insights.sbomify.com/CVE-2020-3118/): Cisco IOS XR Software Discovery Protocol Format String (high 8.8, exploited in the wild)
- [CVE-2020-3569](https://insights.sbomify.com/CVE-2020-3569/): Cisco IOS XR Software DVMRP Memory Exhaustion (high 8.6, exploited in the wild)
- [CVE-2020-3566](https://insights.sbomify.com/CVE-2020-3566/): Cisco IOS XR Software DVMRP Memory Exhaustion (high 8.6, exploited in the wild)
- [CVE-2010-3035](https://insights.sbomify.com/CVE-2010-3035/): Cisco IOS XR Border Gateway Protocol (BGP) Denial-of-Service (high 7.5, exploited in the wild)
- [CVE-2022-20821](https://insights.sbomify.com/CVE-2022-20821/): Cisco IOS XR Open Port (medium 6.5, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-20758 and fix it if it is affected.

What it is: CVE-2022-20758 is a medium-severity denial of service vulnerability in Cisco Ios Xr, published on 15 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-20758 in the wild and no public exploit code.

Affected product: Cisco Ios Xr. 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-2022-20758/ (Markdown: https://insights.sbomify.com/CVE-2022-20758/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-20758
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-20758
- OSV: https://osv.dev/vulnerability/CVE-2022-20758

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-20758/
Summaries are generated and may contain mistakes; the official description above is the record.