CVE-2026-23941: Erlang Erlang/inets vulnerability (CVSS 9.4)

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityLow

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

Affected products

Erlang Erlang/inets≥ 5.10 < 9.1.0.5 · ≥ 9.3 < 9.3.2.3 · ≥ 9.6 < 9.6.1

Erlang Erlang/otp≥ 17.0 < 26.2.5.18 · ≥ 27.0 < 27.3.4.9 · ≥ 28.0 < 28.4.1

Remediation

Fixed in

Erlang Erlang/inets≥ 9.1.0.5

Erlang Erlang/otp≥ 26.2.5.18

Patch & vendor advisories

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-23941 being actively exploited?

CVE-2026-23941 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.45%.

How severe is CVE-2026-23941?

CVE-2026-23941 has a CVSS 3.1 base score of 9.4, rated critical. EPSS estimates a 0.45% probability of exploitation.

Which products are affected by CVE-2026-23941?

Affected products include Erlang Erlang/inets, Erlang Erlang/otp.

How do I fix CVE-2026-23941?

Upgrade affected software to a fixed version, for example Erlang Erlang/inets 9.1.0.5, Erlang Erlang/otp 26.2.5.18 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-23941 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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