What is CVE-2026-123318?

CVE-2026-123318 is a medium-severity vulnerability in Jetbrains Ktor, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 4.8/10. Published 2026-11-06.

How severe is CVE-2026-123318?

Medium severity. CVSS v3 base score is 4.8 out of 10.

Vulnerability in Jetbrains Ktor

CVE-2026-123318

In JetBrains Ktor before 3.6.1 hTTP request smuggling was possible in the CIO engine

Vulnerability class: HTTP Request Smuggling

Published 2026-11-06 · last modified 2026-11-06.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Jetbrains Ktor

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

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

Frequently asked questions

What is CVE-2026-123318?: CVE-2026-123318 is a medium-severity vulnerability in Jetbrains Ktor, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 4.8/10. Published 2026-11-06.
How severe is CVE-2026-123318?: Medium severity. CVSS v3 base score is 4.8 out of 10.