CVE-2021-25761: JetBrains Ktor

Medium severity, CVSS 5.3. EPSS: 0.5% chance of exploitation in the next 30 days.

In JetBrains Ktor before 1.5.0, a birthday attack on SessionStorage key was possible.

Affected products

• JetBrains Ktor: before 1.5.0 (fixed in 1.5.0)

Published 2021-02-03. Last modified 2026-06-17.