CVE-2026-66357

High

Description

httpd has never implemented obs-fold (RFC 2616 §2.2 / RFC 7230 §3.2.4 header continuation lines). Every CRLF followed by a non-CRLF octet unconditionally starts a new header. This missing feature became a security concern as the understanding of HTTP request smuggling attacks evolved. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

SeverityHigh
CVSS8.3
Exploit probability—
ProductErlang\/otp
PublishedSep 1, 2026
First seenSep 1, 2026
Weakness typeCWE-444CWE-444

How to fix

Affected products

ProductAffected versionsFixed in
erlang erlang\/otp17.0 ≤ v < 27.3.4.17, 28.0 ≤ v < 28.5.0.6, 29.0 ≤ v < 29.0.6, 5.10 ≤ v < 9.3.2.7, 9.4 ≤ v < 9.6.2.3, 9.7 ≤ v < 9.7.2, 84adefa331c4159d432d22840663c38f155cd4c127.3.4.17, 28.5.0.6, 29.0.6, 9.3.2.7, 9.6.2.3, 9.7.2

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