CVE-2026-42788— HTTP/2 frame size limit checked after body is buffered in bandit

HTTP/2 frame size limit checked after body is buffered in bandit

Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated memory exhaustion via oversized HTTP/2 frames. 'Elixir.Bandit.HTTP2.Frame':deserialize/2 in lib/bandit/http2/frame.ex checks the SETTINGS_MAX_FRAME_SIZE limit only after pattern-matching payload::binary-size(length), which requires the entire frame body to be present in memory before either the accept or reject clause can fire. A peer that announces a frame length up to the 24-bit maximum (~16 MiB) causes the server to buffer that entire body before the size guard is evaluated, regardless of the max_frame_size negotiated during the HTTP/2 handshake (default 16 KiB per RFC 9113). An unauthenticated attacker holding many concurrent connections can force the server to buffer far more memory than the negotiated frame size limit should permit, leading to memory pressure and potential denial of service. This issue affects bandit: from 0.3.6 before 1.11.0.

N/A

不加限制或调节的资源分配

Bandit 安全漏洞

Bandit是Mat Trudel个人开发者的一款高性能HTTP与WebSocket服务器。 Bandit 0.3.6版本至1.11.0之前版本存在安全漏洞，该漏洞源于HTTP/2帧反序列化时在检查大小限制前缓冲整个帧体，可能导致未经身份验证的内存耗尽。

N/A

N/A