Inconsistent interpretation of HTTP requests in Erlang OTP - CVE-2026-66357
Published: September 2, 2026
Vulnerability identifier: #VU146839
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-66357
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.
The vulnerability exists due to inconsistent interpretation of HTTP requests in the inets httpd server header parser when handling HTTP requests containing obs-fold header continuation lines. A remote attacker can send a specially crafted request to smuggle HTTP requests.
Exploitation requires the server to be deployed behind a reverse proxy that merges obs-fold continuation lines with the preceding header.
Affected software
Erlang OTP
How to mitigate CVE-2026-66357
Install security update from vendor's website.
Erlang OTP - addressed in versions 17.0, 27.3.4.17, 28.5.0.6, 29.0.6