---
id: CVE-2026-6390
title: A flaw was found in GNU nano's multi-buffer error message handling
summary: >-
  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.…
severity: medium
cvss: 6.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H'
cwe:
  - CWE-134
published: '2026-07-23'
updated: '2026-08-21'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-6390'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-6390'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2458767'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00154
epssPercentile: 0.03816
ingestedAt: '2026-08-22T13:32:35.600Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.