CVE-2026-42786
HighSummary
A vulnerability in mtrudel bandit allows for remote denial of service via memory exhaustion, enabling unauthorized users to send an unbounded number of continuation frames. The issue occurs in the handle_frame/3 method, which lacks size limits for accumulated data.
Risk Assessment
The organization may experience significant disruptions in application functionality, leading to service unavailability. Memory exhaustion can result in process crashes, affecting the overall system stability.
Recommendation
It is recommended to update the bandit library to version 1.11.0 or later to mitigate this vulnerability. Additionally, implementing mechanisms to limit the size of transmitted data in the application is advisable.
Other vulnerabilities in bandit
See all- CVE-2026-75484Medium
CRLF Injection vulnerability in the Bandit library allows an unauthenticated remote attacker to smuggle CR, LF, or NUL characters into application-visible request headers via HTTP/2. Header validation does not check field values, allowing them to pass through unchanged. Additionally, a duplicate :authority pseudo-header is accepted, which can lead to conflicts.
- CVE-2026-74836High
A vulnerability in the Bandit library (Elixir) allows an unauthenticated attacker to pin an unbounded number of HTTP/2 stream processes via connection-level flow control. When a response exceeds the connection send window (default 65,535 bytes), the stream process blocks forever, and the queue is never purged, leading to resource exhaustion.
- CVE-2026-65623High
Inefficient algorithmic complexity vulnerability in the bandit library (Elixir), allowing unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly.
- CVE-2026-39805Medium
A vulnerability in the Bandit library (Elixir) allows HTTP request smuggling via duplicate Content-Length headers. The server accepts the first header and treats the remaining data as a subsequent request on the same connection.
Original NVD description (English source)
Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated remote denial of service via memory exhaustion. The fragment reassembly path in 'Elixir.Bandit.WebSocket.Connection':handle_frame/3 in lib/bandit/websocket/connection.ex appends every incoming Continuation{fin: false} frame's payload to a per-connection iolist with no cumulative size cap. The existing max_frame_size option only bounds individual frames; a peer that streams an unbounded number of continuation frames without ever setting fin=1 grows BEAM heap linearly until the OS or a supervisor kills the process. Because the accumulation happens before WebSock.handle_in/2 is called, the application has no opportunity to interpose a size check. Phoenix Channels and LiveView both run over WebSock on Bandit, so a stock Phoenix application exposes this surface as soon as it accepts socket connections. This issue affects bandit: from 0.5.0 before 1.11.0.