Vulnerability · Published Aug 19, 2026 · Assigned by CERT-PL
CVE-2026-65609Out-of-bounds write in nnn
Low 2.4
In plain English
A low-severity out-of-bounds write in nnn from nnn. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities).
Official description
nnn is vulnerable to Out-of-Bound write vulnerability. Due to lack of validation of attacker-controlled length fields deserialized from a session file, a crafted session file can cause nnn to write data beyond the bounds of fixed-size global buffers when loaded with the -s option. An attacker who can place a malicious session file in the victim's nnn session directory can exploit this to corrupt adjacent global state. 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nnn | no fix listed | DEBIAN-CVE-2026-65609 |
| Debian:13 | nnn | no fix listed | DEBIAN-CVE-2026-65609 |
| Debian:14 | nnn | no fix listed | DEBIAN-CVE-2026-65609 |
| Ubuntu:22.04:LTS | nnn | no fix listed | UBUNTU-CVE-2026-65609 |
| Ubuntu:24.04:LTS | nnn | no fix listed | UBUNTU-CVE-2026-65609 |
| Ubuntu:26.04:LTS | nnn | no fix listed | UBUNTU-CVE-2026-65609 |
| Ubuntu:26.10 | nnn | no fix listed | UBUNTU-CVE-2026-65609 |
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
References
- https://cert.pl/en/posts/2026/08/CVE-2026-65609 third-party-advisory