# CVE-2026-94283: Out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser

> A malicious X server can crash X clients via an out-of-bounds read in libX11's XIM attribute parser, requiring an upgrade to libX11.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **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:** 28 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** ALPINE-CVE-2026-94283, AZL-104963, BELL-CVE-2026-94283, DEBIAN-CVE-2026-94283, ECHO-4c1a-f6d4-292c, GHSA-j5qx-6vm4-vfcj, UBUNTU-CVE-2026-94283

## What is CVE-2026-94283?

CVE-2026-94283 is a medium-severity denial of service vulnerability in x.org libX11, published on 28 Sep 2026. 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

An out-of-bounds read vulnerability in libX11's XIM (X Input Method) attribute parser in libX11 before 1.8.14 could be used by malicious X servers to crash attached X clients.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-94283?


## How do I fix CVE-2026-94283?

Upgrade to a fixed version.

## Is CVE-2026-94283 being exploited?

There is no known exploitation of CVE-2026-94283 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-94283 and fix it if it is affected.

What it is: CVE-2026-94283 is a medium-severity denial of service vulnerability in x.org libX11, published on 28 Sep 2026. 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-2026-94283 in the wild and no public exploit code.

Affected product: x.org libX11. 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-2026-94283/ (Markdown: https://insights.sbomify.com/CVE-2026-94283/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-94283
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-94283
- OSV: https://osv.dev/vulnerability/CVE-2026-94283

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-94283/
Summaries are generated and may contain mistakes; the official description above is the record.