CVE-2026-56810

A vulnerability in the Mint library (versions 0.1.0 through 1.9.2) allows HTTP response smuggling by accepting a plus/minus sign in the chunk-size line of Transfer-Encoding: chunked. A malicious HTTP/1 server can exploit this interpretation mismatch to poison the response queue on a shared keep-alive connection, causing subsequent requests to receive forged responses.

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in elixir-mint mint allows a malicious HTTP/1 server to desynchronize a strict intermediary and the Mint client on a pooled connection, enabling response-queue poisoning against subsequent requests that share the connection. Mint.HTTP1.Parse.chunk_size/1 stops at the first non-hexadecimal byte of a chunked response's chunk-size line and returns the remainder unexamined, and Mint.HTTP1.decode_body/5 discards bytes up to the CRLF, so lines such as 5ZZZZZ and 5 9 are accepted as chunk size 5, and 0ZZZZ as the terminating chunk. This issue affects mint from 0.1.0 before 1.10.1.

Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint allows a remote HTTP server to exhaust memory on the client host and cause a denial of service. Two HTTP/1 response-parser states accumulate server data without any cap. In lib/mint/http1.ex, decode_status_line/4 stores the unconsumed data in conn.buffer when the status line is incomplete, and decode_body/5 does the same for an unterminated chunk-extension line. Both wait for a CRLF the server never has to send, and conn.buffer is prepended to every subsequent socket message. The :max_header_list_size budget is wired only into decode_headers/5 and decode_trailer_headers/4, so neither of these states is covered by it. A malicious server, or one reached through an attacker-controlled redirect or a fetched URL, streams bytes indefinitely until the BEAM node is killed by the operating system out-of-memory handler. The chunk-extension variant is reached after a valid status line and a complete, valid header section, so an intermediary inspecting only headers sees an ordinary 200 response. This issue affects mint: from 0.1.0 before 1.10.0.

A vulnerability in the Mint library for Elixir allows a remote HTTP/2 server to exhaust client memory by sending an infinite stream of zero-length CONTINUATION frames. The header accumulation mechanism lacks proper protection against this attack, leading to denial of service (DoS).

A vulnerability in the Mint library for Elixir allows a remote HTTP server to exhaust client memory and cause a denial of service (DoS). The HTTP header decoding functions accumulate headers without limits, and the parser has no cap on the number or size of headers, enabling an attacker to stream infinite header lines without a terminating blank line.

A vulnerability in the Mint library for Elixir allows an attacker-controlled HTTP/2 server to exhaust client memory via a CONTINUATION frame flood. There is no limit on the header accumulator size, leading to memory exhaustion and BEAM process death.

Elixir Mint library before version 1.9.0 is vulnerable to HTTP response smuggling. The Content-Length parser accepts + and - signs, violating RFC 7230. An attacker-controlled HTTP/1 server can desynchronize response framing on shared connections.

A vulnerability in the Mint library for Elixir allows an attacker-controlled HTTP/2 server to exhaust client memory via PUSH_PROMISE flooding. The server can create an unlimited number of stream entries without checking the max_concurrent_streams limit, leading to memory exhaustion.

Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in elixir-mint Mint allows HTTP Request Splitting and HTTP Request Smuggling. In lib/mint/http1/request.ex, the encode_request_line/2 function splices the caller-supplied method and target arguments directly into the HTTP/1 request line without any character validation. An application that forwards attacker-controlled input as the HTTP method or target to Mint.HTTP.request/5 is therefore exposed to request-line CRLF injection. Mint 1.7.0 introduced validate_request_target/2, which rejects CRLF and other control characters in the target by default, but the method field remains unvalidated.