CVE-2026-65610
LowCVSS 2.4Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
nnn stores homelen variable as uchar_t, which can only represent values in the range 0-255. An attacker who can influence the victim's execution environment can provide an arbitrary HOME path with length that is truncated to 0. The expression (homelen - 1) is promoted to signed int and becomes -1, producing an out-of-bounds read and an out-of-bounds write one byte before the path buffer. Only version 5.2 was tested and confirmed as vulnerable.
Risk Assessment
The risk is the possibility of out-of-bounds read and write, which could lead to program crashes, data disclosure, or potentially code execution depending on the context.
Recommendation
It is recommended to update nnn to the latest available version if a fix has been released, or to avoid using nnn in environments where an attacker can control the HOME variable.
Original NVD description (English source)
nnn stores homelen variable as uchar_t, which can only represent values in the range 0-255. An attacker who can influence the victim's execution environment can provide an arbitrary HOME path with length that is truncated to 0. The expression (homelen - 1) is promoted to signed int and becomes -1 and producing an out-of-bounds read and an out-of-bounds write one byte before the path buffer. Maintainer of this project was notified about this vulnerability. It might has been addressed, but the maintainer did not provide a vulnerable version range. Only version 5.2 was tested and confirmed as vulnerable.