CVE-2026-123317: JetBrains Ktor · Improper Validation of Integrity Check Value
Affects JetBrains KtorSource CVE Database V5
Not known to be exploited · CVSS 8.1 High : upgrade to 3.6.1 soon.
Data as of 6 Nov 2026, 10:49 UTC
Thin evidence
One scorer or none| CNA (JetBrains) | CVSS 3.1 | 8.1 |
|---|
- Patch
- Available – fixed in 3.6.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade JetBrains Ktor to 3.6.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| JetBrainsKtor | Affected
| Fixed in
|
AI-suggested
Upgrade JetBrains Ktor to version 3.6.1 or later, where this vulnerability is fixed. No additional mitigation is required once the update is applied.
Description
CVE-2026-123317 is a vulnerability in JetBrains Ktor versions before 3.6.1 that allows session forgery through tampered encrypted session cookies due to improper validation of integrity check values. This flaw enables attackers with low privileges to compromise session integrity without user interaction. The issue is fixed in version 3.6.1.