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Erlang\/inetsApplication · Erlang

CVE-2026-23941

CRITICAL · 9.4 CVSS v3.1 Published 2026-03-13
Fix available
A fix is available. Upgrade to 9.1.0.5 / 9.3.2.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in Erlang OTP (inets httpd module) allows HTTP Request Smuggling. This vulnerability is associated with program files lib/inets/src/http_server/httpd_request.erl and program routines httpd_request:parse_headers/7. The server does not reject or normalize duplicate Content-Length headers. The earliest Content-Length in the request is used for body parsing while common reverse proxies (nginx, Apache httpd, Envoy) honor the last Content-Length value. This violates RFC 9112 Section 6.3 and allows front-end/back-end desynchronization, leaving attacker-controlled bytes queued as the start of the next request. This issue affects OTP from OTP 17.0 before OTP 28.4.1, OTP 27.3.4.9 and OTP 26.2.5.18, corresponding to inets from 5.10 before 9.6.1, 9.3.2.3 and 9.1.0.5.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Erlang\/inetsApplication
Affected:>= 5.10, < 9.1.0.5>= 9.3, < 9.3.2.3>= 9.6, < 9.6.1
Erlang\/otpApplication
Affected:>= 17.0, < 26.2.5.18>= 27.0, < 27.3.4.9>= 28.0, < 28.4.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 9.1.0.5 / 9.3.2.3 / 9.6.1 or later
Fixed in 9.1.0.59.3.2.39.6.1
Vendor patch github.com →
Recommended fix High confidence

OTP 26.2.5.18+ / OTP 27.3.4.9+ / OTP 28.4.1+ (or inets 9.1.0.5+ / 9.3.2.3+ / 9.6.1+)

  1. Identify the currently installed Erlang/OTP and inets versions using 'erl -version' or by checking your project's rebar.config or erlang.mk
  2. Determine which major OTP release line you are on (OTP 26.x, 27.x, or 28.x)
  3. Upgrade to the minimum fixed version for your release line: OTP 26.x users upgrade to 26.2.5.18 or later; OTP 27.x users upgrade to 27.3.4.9 or later; OTP 28.x users upgrade to 28.4.1 or later
  4. If using inets directly, ensure the corresponding inets version is also updated: inets 9.1.x → 9.1.0.5+, inets 9.3.x → 9.3.2.3+, inets 9.6.x → 9.6.1+
  5. Rebuild and redeploy your application with the patched OTP/inets versions
  6. Restart all running Erlang nodes to load the fixed code
Caveat Minor: This is a security patch with no expected breaking changes; however, verify your application's behavior with duplicate headers as the server will now reject such requests per RFC 9112

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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