# CVE-2026-6390: Memory corruption in Red Hat Enterprise Linux 10

> A format string vulnerability in GNU nano allows attackers to disclose stack information, crash the application, or potentially execute arbitrary code via crafted filenames.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 23 Jul 2026
- **Updated:** 1 Sep 2026
- **Also known as:** AZL-93270, BELL-CVE-2026-6390, DEBIAN-CVE-2026-6390, ECHO-7a9e-a9fb-a110, GHSA-cgrj-mh7v-v4c8, OESA-2026-3810, OESA-2026-3811, OESA-2026-3812, OESA-2026-3813, UBUNTU-CVE-2026-6390, openSUSE-SU-2026:12247-1

## What is CVE-2026-6390?

CVE-2026-6390 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 23 Jul 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 GNU nano's multi-buffer error message handling. When a user opens multiple files at startup and one triggers an ALERT-level error, a specially crafted filename containing printf format specifiers can be reinterpreted. This format string vulnerability may allow an attacker to achieve stack information disclosure, cause a denial of service (crash), or potentially perform arbitrary memory writes.

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

## Which versions are affected by CVE-2026-6390?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `nano` | openSUSE:Tumbleweed | All versions | 9.3-1.1 |

## How do I fix CVE-2026-6390?

Apply the vendor's patch.

## Is CVE-2026-6390 being exploited?

There is no known exploitation of CVE-2026-6390 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-6390 and fix it if it is affected.

What it is: CVE-2026-6390 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 23 Jul 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-2026-6390 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2026-6390/ (Markdown: https://insights.sbomify.com/CVE-2026-6390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-6390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6390
- OSV: https://osv.dev/vulnerability/CVE-2026-6390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-6390/
Summaries are generated and may contain mistakes; the official description above is the record.