inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation (CVE-2026-66357) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-66357

inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation

Answer in brief

CVE-2026-66357 records a Unknown severity vulnerability in inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation. The current sources do not mark it as known exploited. The current feed maps Erlang/OTP (generic), Erlang/OTP (generic), Erlang/OTP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 1, 2026Updated Sep 1, 2026Source checked Sep 1, 2026First seen by HOL Sep 1, 2026Material review Sep 1, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Erlang/OTP (generic), Erlang/OTP (generic), Erlang/OTP (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Erlang/OTPgeneric	>=17.0 <27.3.4.17 \|\| >=28.0 <28.5.0.6 \|\| >=29.0 <29.0.6	27.3.4.17, 28.5.0.6, 29.0.6
Erlang/OTPgeneric	>=5.10 <9.3.2.7 \|\| >=9.4 <9.6.2.3 \|\| >=9.7 <9.7.2	9.3.2.7, 9.6.2.3, 9.7.2
Erlang/OTPgeneric	>=84adefa331c4159d432d22840663c38f155cd4c1 <*	*

Recommended response

Check inventory. Check lockfiles and deployed manifests for Erlang/OTP, Erlang/OTP, Erlang/OTP.
Review the reported fix. Update Erlang/OTP to 27.3.4.17; Erlang/OTP to 9.3.2.7; Erlang/OTP to * if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 1, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.