GNU nano multi-buffer format string vulnerability
CVE-2026-6390 Published on July 23, 2026
Nano: gnu nano: arbitrary memory writes, information disclosure, or denial of service via format string vulnerability in error handling.
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.
Vulnerability Analysis
CVE-2026-6390 is exploitable with local system access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality, a high impact on integrity and availability.
Timeline
Reported to Red Hat.
Made public. 98 days later.
Weakness Type
Use of Externally-Controlled Format String
The software uses a function that accepts a format string as an argument, but the format string originates from an external source.
Products Associated with CVE-2026-6390
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