CVE-2026-66357CWE-444

CVE-2026-66357

published September 1, 2026

CVSS
8.3
EPSS
1%
Percentile
46.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS
8.3 · NONE
CVSS v4.0
8.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:L/SA:N
EPSS
0.00577 · 46.8th percentile
Weakness
CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Published
2026-09-01T19:17Z
References (6)
https://github.com/erlang/otp/commit/273d8958de38ff2a7fe0c5dcc5b6bfe6f65717f3 · 6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://cna.erlef.org/cves/CVE-2026-66357.html · 6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/erlang/otp/commit/220d618d2479a7180b4a06d0c5aacfaa4af4a85b · 6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/erlang/otp/commit/e640d599287d2eba919e6f13b91f042d7dbe6ff4 · 6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/erlang/otp/security/advisories/GHSA-qh2f-33hj-37qf · 6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://osv.dev/vulnerability/EEF-CVE-2026-66357 · 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
EPSS history
Timeline
  • 03 SEP 03:31Z
    EPSS moved — → 0%
    epss
  • 01 SEP 14:40Z
    inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation
    cvelistv5