# CVE-2020-11743: Denial of service in n/a

> A malicious guest OS can crash the Linux-based dom0 or backend domain by exploiting a logic error in Xen's grant table mapping error handling.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** Yes
- **Published:** 14 Apr 2020
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-11743, DEBIAN-CVE-2020-11743, GHSA-ff8p-26v5-2cw5, UBUNTU-CVE-2020-11743

## What is CVE-2020-11743?

CVE-2020-11743 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 14 Apr 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of a bad error path in GNTTABOP_map_grant. Grant table operations are expected to return 0 for success, and a negative number for errors. Some misplaced brackets cause one error path to return 1 instead of a negative value. The grant table code in Linux treats this condition as success, and proceeds with incorrectly initialised state. A buggy or malicious guest can construct its grant table in such a way that, when a backend domain tries to map a grant, it hits the incorrect error path. This will crash a Linux based dom0 or backend domain.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2020-11743?

It affects 2 products.


Products: Fedoraproject Fedora, Xen Xen.

## How do I fix CVE-2020-11743?

Apply the vendor's patch.

## Is CVE-2020-11743 being exploited?

There is no known exploitation of CVE-2020-11743 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-11743 and fix it if it is affected.

What it is: CVE-2020-11743 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 14 Apr 2020. 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-2020-11743 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2020-11743/ (Markdown: https://insights.sbomify.com/CVE-2020-11743/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-11743
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-11743
- OSV: https://osv.dev/vulnerability/CVE-2020-11743

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-11743/
Summaries are generated and may contain mistakes; the official description above is the record.