CVE-2026-123317: JetBrains Ktor session forgery in encrypted cookies
CVE-2026-123317 · Severity: high · CVSS 8.1 · Published 2026-11-06
JetBrains Ktor is a web framework used to build server applications. An attacker could tamper with encrypted session cookies to forge sessions, allowing them to impersonate legitimate users and access their accounts or data without valid credentials.
No. Junglewise Threat Intelligence has no report of CVE-2026-123317 being exploited in the wild.
How severe is CVE-2026-123317?
High severity, with a CVSS score of 8.1, published 6 November 2026.
Which products and versions are affected?
Jetbrains Ktor before 3.6.1.
Is there a fix for CVE-2026-123317?
Yes: fixed in 3.6.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-123317 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-123317?
Check whether you run Jetbrains Ktor at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.