CVE-2026-23941
CriticalCVSS 9.4Exploitation Probability (EPSS)
Low risk41th percentile - higher than 41% of all known CVEs
Summary
In Erlang OTP (inets httpd module), an HTTP Request Smuggling vulnerability exists. The server does not reject or normalize duplicate Content-Length headers. The first value is used, while common proxies use the last, enabling front-end/back-end desynchronization and injection of attacker-controlled bytes as the start of the next request.
Risk Assessment
An attacker can smuggle HTTP requests, potentially bypassing security controls, stealing data, or performing unauthorized actions.
Recommendation
Update Erlang OTP to version 28.4.1, 27.3.4.9, or 26.2.5.18 (or later).
Other vulnerabilities in Erlang OTP
See all- CVE-2026-28808Critical
An incorrect authorization vulnerability in Erlang OTP (inets modules) allows unauthenticated access to CGI scripts protected by directory rules when served via script_alias. The path mismatch between access control evaluation and script execution allows bypassing protections.
- CVE-2025-32433CriticalActively exploited
Erlang/OTP prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20 contains a vulnerability in the SSH server that may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access and execute arbitrary commands without valid credentials.
- CVE-2016-10253Critical
An issue was discovered in Erlang/OTP 18.x related to the generation of compiled regular expressions, which is vulnerable to a heap overflow. Regular expressions using a malformed extpattern can indirectly specify an offset used as an array index.
- CVE-2026-75538High
In Erlang/OTP, when using the inet driver with {packet,4} mode, an attacker connecting to an open TCP port can exploit a signed overflow in packet length calculation, potentially overflowing the receive buffer and crashing the BEAM VM.
- CVE-2026-74835High
The httpd HTTP server in the inets application fails to enforce a configured body-size limit on chunked requests. This may allow sending very large requests, potentially leading to server overload.
- CVE-2026-73812High
The check_header/3 function in httpd rejects duplicate Content-Length but does not check for the co-presence of Transfer-Encoding and Content-Length, which can lead to request smuggling desynchronization between front-end and back-end.
- CVE-2026-73276High
Gracefulness code ignored cases that should be rejected, resulting in possible HTTP Request Smuggling opportunities.
- CVE-2026-58227High
A vulnerability in the Erlang/OTP SSL application allows memory exhaustion by sending a crafted certificate chain during TLS/DTLS handshake. Lack of cycle detection in the certificate chain building function causes unbounded recursion, leading to BEAM node crash.
- CVE-2026-55953High
The TLS 1.2 (and earlier) and DTLS client in Erlang/OTP does not verify that the cipher suite selected by the server in ServerHello was among the suites offered by the client. An on-path attacker can select an anonymous cipher suite, bypassing certificate and hostname verification, allowing interception and modification of traffic.
- CVE-2026-55737High
In Erlang OTP, a signed to unsigned conversion error and out-of-bounds heap write vulnerability exists when decoding a crafted ETF binary via binary_to_term/1. This can corrupt the BEAM heap pointer and crash the virtual machine.
Original NVD description (English source)
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 data from NVD (NIST) · CISA KEV · EPSS