# CVE-2021-1370: Privilege escalation in Cisco IOS XR Software

> An authenticated local attacker can escalate privileges to root on Cisco IOS XR routers by exploiting insufficient validation in a CLI command.

- **Severity:** High 7.8 (`CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Feb 2021
- **Updated:** 8 Nov 2024
- **Also known as:** GHSA-g2w2-8h95-w988

## What is CVE-2021-1370?

CVE-2021-1370 is a high-severity vulnerability in Cisco Ios Xr, published on 4 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in a CLI command of Cisco IOS XR Software for the Cisco 8000 Series Routers and Network Convergence System 540 Series Routers running NCS540L software images could allow an authenticated, local attacker to elevate their privilege to root. To exploit this vulnerability, an attacker would need to have a valid account on an affected device. The vulnerability is due to insufficient validation of command line arguments. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the prompt. A successful exploit could allow an attacker with low-level privileges to escalate their privilege level to root.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2021-1370?

It affects 1 product.


Products: Cisco Ios Xr.

## How do I fix CVE-2021-1370?

No fix has been published for CVE-2021-1370 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-1370 being exploited?

There is no known exploitation of CVE-2021-1370 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-2021-1370 and fix it if it is affected.

What it is: CVE-2021-1370 is a high-severity vulnerability in Cisco Ios Xr, published on 4 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-1370 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-2021-1370/ (Markdown: https://insights.sbomify.com/CVE-2021-1370/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-1370
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-1370
- OSV: https://osv.dev/vulnerability/CVE-2021-1370

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-1370/
Summaries are generated and may contain mistakes; the official description above is the record.