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CVE-2026-73812— inets, httpd: HTTP Request Smuggling via Transfer-Encoding and Content-Length

Quick assessment

Affected
Erlang OTP
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

httpd 的 函数会根据 CVE-2026-23941 拒绝重复的 Content-Length 头，但从未检查 RFC 9112 第 6.3 节所指的“TE（Transfer-Encoding）与 CL（Content-Length）同时存在”的情况，而该情况被视为可能的请求走私（smuggling）尝试。 以分块（chunked）方式处理请求体，并静默丢弃 Content-Length 头。当使用“优先采用 CL”的前端网关与“优先采用分块编码”的后端 inets 服务器配合时，就会形成典型的“前端基于 CL

CVSS 8.3 · High

Possible ATT&CK Techniques 1 AI

T1011.001 · Exfiltration Over Bluetooth
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I. Basic Information for CVE-2026-73812

Vulnerability Information
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Vulnerability Title
inets, httpd: HTTP Request Smuggling via Transfer-Encoding and Content-Length
Source: CVE Program / CVE List V5
Vulnerability Description
httpd function check_header/3 rejects duplicate Content-Length (per CVE-2026-23941) but never checks for the TE+CL co-presence that RFC 9112 §6.3 identifies as a probable smuggling attempt. handle_body/3 frames by chunked and silently discards Content-Length. A CL-preferring front-end paired with chunked-preferring inets creates a classic CL.TE front-end/back-end desync. 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
HTTP请求的解释不一致性(HTTP请求私运)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Erlang OTP 17.0 ~ 27.3.4.17 cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Erlang OTP 5.10 ~ 9.3.2.7 cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Erlang OTP 84adefa331c4159d432d22840663c38f155cd4c1 ~ 591dc00dc99dc2a426167a3b5257c0c94bd45e91 cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*

II. Public POCs for CVE-2026-73812

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III. Intelligence Information for CVE-2026-73812

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Other References for CVE-2026-73812 (4)

Same Patch Batch · Erlang · 2026-09-01 · 8 CVEs total

CVE-2026-71380 8.7 HIGH httpd applies no timeout while receiving a request body, parking a worker on a stalled cli
CVE-2026-70399 8.7 HIGH httpd does not enforce the documented default max_clients connection limit
CVE-2026-66357 8.3 HIGH inets,httpd:HTTP Request Smuggling via obs-fold Header Continuation
CVE-2026-73276 8.3 HIGH inets, httpd: HTTP Request Smuggling via Whitespace-Before-Colon Header Dropping i
CVE-2026-55951 8.2 HIGH httpc memory exhaustion via unbounded response header accumulation
CVE-2026-59696 6.9 MEDIUM uri_string does not bound the port component of a URI before integer conversion
CVE-2026-71562 6.3 MEDIUM httpc does not bound server-supplied numeric header values before integer conversion

IV. Related Vulnerabilities

Same product: OTP
Same vendor: Erlang
Same weakness: CWE-444

V. Comments for CVE-2026-73812

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