Inconsistent interpretation of HTTP requests in Ktor - CVE-2026-123318
Published: November 6, 2026
Vulnerability identifier: #VU159681
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-123318
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to smuggle HTTP requests and potentially bypass request-handling security controls.
The vulnerability exists due to inconsistent interpretation of HTTP request boundaries in the CIO engine when processing HTTP traffic. A remote attacker can send specially crafted HTTP requests to cause HTTP components to disagree about request boundaries, potentially enabling unauthorized request processing.
Affected software
Ktor
How to mitigate CVE-2026-123318
Install security update from vendor's website.
Ktor - update to 3.6.1