# CVE-2023-43785: Libx11: out-of-bounds memory access in _xkbreadkeysyms()

> A local attacker can exploit an out-of-bounds read in libX11 to disclose sensitive memory contents from the system.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 10 Oct 2023
- **Updated:** 6 Nov 2025
- **Also known as:** ALPINE-CVE-2023-43785, AZL-31320, BELL-CVE-2023-43785, CLSA-2025-1745588411, DEBIAN-CVE-2023-43785, GHSA-9368-fgh5-gh2f, JLSEC-2026-473, UBUNTU-CVE-2023-43785

## What is CVE-2023-43785?

CVE-2023-43785 is a medium-severity vulnerability in Fedoraproject Fedora, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A vulnerability was found in libX11 due to a boundary condition within the _XkbReadKeySyms() function. This flaw allows a local user to trigger an out-of-bounds read error and read the contents of memory on the system.

Weakness: CWE-125 (Out-of-bounds Read), CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2023-43785?

It affects 3 products.


Products: Fedoraproject Fedora, Redhat Enterprise Linux, X.org Libx11.

## How do I fix CVE-2023-43785?

Apply the vendor's patch.

## Is CVE-2023-43785 being exploited?

There is no known exploitation of CVE-2023-43785 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-2023-43785 and fix it if it is affected.

What it is: CVE-2023-43785 is a medium-severity vulnerability in Fedoraproject Fedora, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-43785 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-2023-43785/ (Markdown: https://insights.sbomify.com/CVE-2023-43785/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-43785
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-43785
- OSV: https://osv.dev/vulnerability/CVE-2023-43785

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-43785/
Summaries are generated and may contain mistakes; the official description above is the record.