Vulnerability in Erlang Erlang\/inets
CVE-2026-23941
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.
Vulnerability class: HTTP Request Smuggling
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.005 (36.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: -0.001
Affected products
- Erlang Erlang\/inets
- Erlang Erlang\/otp
- Erlang Otp — versions 5.10, 17.0, 84adefa331c4159d432d22840663c38f155cd4c1
Weakness classification (CWE)
References
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, vendor-advisory, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Third Party Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Product, x_version-scheme)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
Frequently asked questions
- What is CVE-2026-23941?
- CVE-2026-23941 is a critical-severity vulnerability in Erlang Erlang\/inets, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.4/10. Published 2026-03-13.
- How severe is CVE-2026-23941?
- Critical severity. CVSS v3 base score is 9.4 out of 10.