Session Forgery Vulnerability in JetBrains Ktor
CVE-2026-123317

8.1HIGH

Key Information:

Vendor

Jetbrains
Status
Ktor
Vendor
CVE Published:
6 November 2026

What is CVE-2026-123317?

A vulnerability exists in JetBrains Ktor, allowing session forgery through tampered encrypted session cookies. This flaw could allow an attacker to manipulate session data and gain unauthorized access to user sessions. Users are encouraged to upgrade to Ktor version 3.6.1 or later to mitigate the risks associated with this vulnerability. Ongoing monitoring and security best practices are recommended to safeguard against potential exploitation.

Affected Version(s)

Ktor 0 < 3.6.1

References

https://www.jetbrains.com/privacy-security/issues-fixed/

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.