CVE-2026-6390
Received Received - Intake

GNU nano format string vulnerability in multi-buffer error handling

Publication date: 2026-07-23

Last updated on: 2026-07-23

Assigner: Red Hat, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-07-23
Last Modified
2026-07-23
Generated
2026-07-23
AI Q&A
2026-07-23
EPSS Evaluated
N/A
NVD
CVE-2026-6390
EUVD
EUVD-2026-47874

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
gnu nano From 2026-04-15 (inc) to 2026-07-28 (inc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-134 The product uses a function that accepts a format string as an argument, but the format string originates from an external source.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a format string vulnerability in GNU nano's error handling when opening multiple files. If one file triggers an ALERT error, a crafted filename with printf format specifiers could allow stack information disclosure, denial of service, or arbitrary memory writes.

Detection Guidance

To detect this vulnerability, check if GNU nano is installed and inspect the version. Look for filenames with printf format specifiers in error logs when opening multiple files. Commands like 'nano --version' or 'dpkg -l | grep nano' can help verify the installed version.

Impact Analysis

An attacker could exploit this to crash the program, leak sensitive memory contents, or potentially execute arbitrary code on your system if they can control filenames opened by nano.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR or HIPAA as it involves a format string flaw in GNU nano's error handling. However, if exploited, it could lead to information disclosure or arbitrary memory writes, which might indirectly impact data confidentiality requirements under these regulations.

Mitigation Strategies

Update GNU nano to the latest patched version as soon as it becomes available. Avoid opening multiple files from untrusted sources. Monitor Red Hat Bugzilla for updates and apply security patches promptly.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-6390. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart