# CVE-2026-6843: Nano: nano: format string vulnerability leads to denial of service

> A local attacker can cause a denial of service in the Nano text editor by creating a directory with a name containing printf specifiers.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Apr 2026
- **Updated:** 1 Sep 2026
- **Also known as:** AZL-85560, CLSA-2026-1780920842, DEBIAN-CVE-2026-6843, GHSA-9jvr-742w-rwph, UBUNTU-CVE-2026-6843

## What is CVE-2026-6843?

CVE-2026-6843 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 22 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

A flaw was found in nano. A local user could exploit a format string vulnerability in the `statusline()` function. By creating a directory with a name containing `printf` specifiers, the application attempts to display this name, leading to a segmentation fault (SEGV). This results in a Denial of Service (DoS) for the `nano` application.

Weakness: CWE-134 (Use of Externally-Controlled Format String)

## Which versions are affected by CVE-2026-6843?

It affects 3 products.


Products: Gnu Nano, Redhat Enterprise Linux, Redhat Openshift Container Platform.

## How do I fix CVE-2026-6843?

Apply the vendor's patch.

## Is CVE-2026-6843 being exploited?

There is no known exploitation of CVE-2026-6843 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2024-5742](https://insights.sbomify.com/CVE-2024-5742/): Path traversal in Red Hat Enterprise Linux 10 (medium 6.7)
- [CVE-2010-1161](https://insights.sbomify.com/CVE-2010-1161/): Race condition in n/a (low 3.7)
- [CVE-2010-1160](https://insights.sbomify.com/CVE-2010-1160/): Path traversal in n/a (low 1.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6843 and fix it if it is affected.

What it is: CVE-2026-6843 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 22 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-6843 in the wild and no public exploit code.

Affected product: Redhat Enterprise Linux. 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-2026-6843/ (Markdown: https://insights.sbomify.com/CVE-2026-6843/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6843
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6843
- OSV: https://osv.dev/vulnerability/CVE-2026-6843

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6843/
Summaries are generated and may contain mistakes; the official description above is the record.