# CVE-2021-1440: Cisco IOS XR Software BGP Resource Public Key Infrastructure Denial of Service Vulnerability

> Remote attackers can crash the BGP process on Cisco IOS XR devices by sending crafted RPKI packets, causing a denial of service.

- **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:** 18 Nov 2024
- **Updated:** 18 Nov 2024
- **Also known as:** GHSA-g8j6-3mwg-7x4g

## What is CVE-2021-1440?

CVE-2021-1440 is a medium-severity denial of service vulnerability in Cisco Ios Xr, published on 18 Nov 2024. 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 Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Border Gateway Protocol (BGP) process to crash, resulting in a denial of service (DoS) condition.
This vulnerability is due to the incorrect handling of a specific RPKI to Router (RTR) Protocol packet header. An attacker could exploit this vulnerability by compromising the RPKI validator server and sending a specifically crafted RTR packet to an affected device. Alternatively, the attacker could use man-in-the-middle techniques to impersonate the RPKI validator server and send a specifically crafted RTR response packet over the established RTR TCP connection to the affected device. A successful exploit could allow the attacker to cause a DoS condition because the BGP process could constantly restart and BGP routing could become unstable.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see .

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2021-1440?

It affects 1 product.


Products: Cisco Ios Xr.

## How do I fix CVE-2021-1440?

No fix has been published for CVE-2021-1440 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-1440 being exploited?

There is no known exploitation of CVE-2021-1440 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-2021-1440 and fix it if it is affected.

What it is: CVE-2021-1440 is a medium-severity denial of service vulnerability in Cisco Ios Xr, published on 18 Nov 2024. 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-2021-1440 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-2021-1440/ (Markdown: https://insights.sbomify.com/CVE-2021-1440/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1440
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1440
- OSV: https://osv.dev/vulnerability/CVE-2021-1440

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-1440/
Summaries are generated and may contain mistakes; the official description above is the record.