inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation
Summary
| CVE | CVE-2026-66357 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-01 15:17:23 UTC |
| Updated | 2026-09-08 01:17:51 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 8.3 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.003280000 probability, percentile 0.253810000 (date 2026-09-03)
Problem Types: CWE-444 | CWE-444 CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 8.3 | HIGH | 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/E:X/C... |
| 4.0 | CNA | CVSS | 8.3 | HIGH | 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 |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
LowIntegrity
HighAvailability
NoneSub Conf.
NoneSub Integrity
LowSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Erlang | OTP | unknown 17.0 otp | Not specified |
| CNA | Erlang | OTP | affected 17.0 27.3.4.17 otp | Not specified |
| CNA | Erlang | OTP | affected 28.0 28.5.0.6 otp | Not specified |
| CNA | Erlang | OTP | affected 29.0 29.0.6 otp | Not specified |
| CNA | Erlang | OTP | unknown 5.10 otp | Not specified |
| CNA | Erlang | OTP | affected 5.10 9.3.2.7 otp | Not specified |
| CNA | Erlang | OTP | affected 9.4 9.6.2.3 otp | Not specified |
| CNA | Erlang | OTP | affected 9.7 9.7.2 otp | Not specified |
| CNA | Erlang | OTP | affected 84adefa331c4159d432d22840663c38f155cd4c1 * git | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/erlang/otp/security/advisories/GHSA-qh2f-33hj-37qf | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/erlang/otp/commit/220d618d2479a7180b4a06d0c5aacfaa4af4a85b | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/erlang/otp/commit/e640d599287d2eba919e6f13b91f042d7dbe6ff4 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| github.com/erlang/otp/commit/273d8958de38ff2a7fe0c5dcc5b6bfe6f65717f3 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | |
| cna.erlef.org/cves/CVE-2026-66357.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | |
| osv.dev/vulnerability/EEF-CVE-2026-66357 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Lukas Backström / Erlang Solutions (en)
CNA: Konrad Pietrzak / Ericsson (en)
There are currently no legacy QID mappings associated with this CVE.