CVE-2026-108525

HTTP/2 inbound flow control is not enforced, letting a client queue unbounded DATA in stream processes in Bandit

State
Published
Severity
8.7 High
Published
Oct 26, 2026
Updated
Oct 26, 2026
Reserved
Oct 15, 2026

Read the record on cve.org

Description

Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory via DATA frames sent past the advertised receive window. The attacker requests a response larger than the 65,535-byte initial window and withholds WINDOW_UPDATE, so the stream process blocks while sending and stops reading, then floods small DATA frames on that stream. Every frame is queued in the stream's mailbox until the BEAM node runs out of memory.

Bandit.HTTP2.Connection.handle_frame/3 in lib/bandit/http2/connection.ex forwards each DATA frame to the stream process without consulting the receive window, and Bandit.HTTP2.FlowControl.compute_recv_window/2 replenishes the window as data arrives rather than as it is consumed, and never answers a violation with FLOW_CONTROL_ERROR.

This issue affects bandit: from 0.3.1 before 1.14.0.

Scores

CVSSScoreVectorSource
4.08.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NEEF

Weaknesses

  • CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

ProductVersions
banditmtrudel
  • 0.3.1 to before 1.14.0Affected
banditmtrudel
  • c8dc1e97050cf359f61ed6cdd110f3cdaf1d6f5f to before 220b9dfd27f9a21305be2afc75cbe585ddc24e7aAffected

References

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