Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint (Mint.HTTP1 module) allows a denial of service via an oversized chunked transfer-encoded response.

This vulnerability is associated with program files lib/mint/http1.ex and program routines 'Elixir.Mint.HTTP1':decodebody/5, 'Elixir.Mint.HTTP1':addbodytobuffer/2.

When Mint decodes a chunked HTTP response body, it accumulates each partial fragment of the current chunk in the connection's databuffer (an unbounded iolist) via addbodytobuffer/2 and does not emit the data to the caller until the full declared chunk length has been received. The chunk size is taken directly from the server and parsed with no upper bound, so a malicious or compromised server can announce one enormous chunk (for example a size line of 7FFFFFFF, about 2 GiB) and then send the body bytes slowly without ever completing the chunk. The client buffers every received byte while it waits for a completion that never arrives, and because no data responses are produced until the chunk finishes, a caller that otherwise streams large content-length bodies safely gains no protection. An unauthenticated remote server (reachable whenever a client follows redirects, fetches user-supplied URLs, or processes webhooks) can drive the client's memory arbitrarily high and trigger an out-of-memory condition.

This issue affects mint: from 0.5.0 before 1.9.1.

Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP server to exhaust memory on the client host and cause a denial of service.

The Mint.HTTP1.decodeheaders/5 and Mint.HTTP1.decodetrailerheaders/4 functions in lib/mint/http1.ex accumulate every parsed response header and chunked-trailer field into a per-request list that persists across incoming TCP segments as request.headersbuffer, and only clear it when the terminating blank line is received. The section has no cap on the number of headers or on total bytes, and the underlying :erlang.decodepacket(:httphbin, binary, []) parser is invoked with an empty option list so its per-line and per-packet size limits also default to unlimited.

A malicious HTTP server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can stream complete header lines (or, after a chunked body, complete trailer lines) indefinitely without ever emitting the terminating blank line. The connection state grows without bound until the BEAM node is killed by the operating system's out-of-memory handler, taking down the entire application that uses Mint as an HTTP client.

This issue affects mint: from 0.1.0 before 1.9.2.

Allocation of resources without limits vulnerability in elixir-mint mint allows a remote HTTP/2 server to exhaust memory on the client host and cause a denial of service.

The Mint.HTTP2.handlecontinuation/3 function in lib/mint/http2.ex accumulates the header-block fragment carried by each HTTP/2 CONTINUATION frame into a growing conn.headersbeingprocessed nesting, one level deeper per frame, and only releases it when a frame with the ENDHEADERS flag arrives. The only guard on this accumulator is Mint.HTTP2.assertheaderblockwithinmaxsize/2, which sums the byte size of the fragments received so far. Because a CONTINUATION frame is permitted by the protocol to carry a zero-length payload, an unbounded chain of zero-length CONTINUATION frames adds no bytes to the running total, never trips the size cap, and never emits ENDHEADERS, yet each frame still nests the accumulator one level deeper.

A malicious HTTP/2 server (reachable directly, via an attacker-controlled redirect, via SSRF, or via a man-in-the-middle) can open a stream by sending a HEADERS frame without ENDHEADERS and then stream zero-length CONTINUATION frames indefinitely. Client memory grows one cons cell per frame received; sustained bandwidth from the peer drives the BEAM node running the Mint client to memory exhaustion and eventual out-of-memory termination.

This issue affects mint: from 0.1.0 before 1.9.2.

Inefficient Algorithmic Complexity vulnerability in elixir-mint mint allows a remote HTTP server to exhaust CPU on the client host and cause a denial of service.

parsehexprefix/2 in lib/mint/http1/parse.ex folds each hex digit of a chunked response's chunk-size field into an arbitrary-precision accumulator with acc 16 + digit and imposes no limit on the digit count. Because the accumulator grows without bound, the multiplication is not constant time and one pass over N digits costs O(N squared). handledata/2 prepends conn.buffer and re-parses from the start on every socket message, so a server that dribbles the digits out in small packets makes the client pay that cost repeatedly. A run of roughly 512,000 hex digits costs over ten seconds of CPU in a single pass, measured on stock defaults. The parser reaches this state 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 1.9.3 before 1.10.0.