Medium (5.3). EPSS 2.6% chance of exploitation in the next 30 days. Fixed in org.jetbrains.kotlin:kotlin-stdlib 1.4.21.
In JetBrains Kotlin before 1.4.21, a vulnerable Java API was used for temporary file and folder creation. An attacker was able to read data from such files and list directories due to insecure permissions.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS
2.6% chance of exploitation in the next 30 days; higher than 85% of CVEs (scores of 2026-10-31)