The QNAP TS-239 Pro and TS-639 Pro with firmware 2.1.7 0613, 3.1.0 0627, and 3.1.1 0815 use the rand library function to generate a certain recovery key, which makes it easier for local users to determine this key via a brute-force attack.
Severity
CVSS 3.1
5.5 medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS
0.4% chance of exploitation in the next 30 days; higher than 35% of CVEs (scores of 2026-10-31)