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.

Format string vulnerability in nano's statusline(). Directory names containing printf specifiers (%s) are stored in errormessage and later passed as format string to statusline() with no args. Causes stack reads and SEGV.

Verified on nano 8.7 with ASAN. BZ#2455127. Reported by Michał Majchrowicz and Marcin Wyczechowski, AFINE Team.

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.

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.

A vulnerability was found in GNU Nano that allows a possible privilege escalation through an insecure temporary file. If Nano is killed while editing, a file it saves to an emergency file with the permissions of the running user provides a window of opportunity for attackers to escalate privileges through a malicious symlink.