CVE-2026-42788

Description

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.

PUBLISHED Reserved 2026-04-29 | Published 2026-05-01 | Updated 2026-05-04 | Assigner EEF

Problem types

CWE-770 Allocation of Resources Without Limits or Throttling

Product status

Credits

Peter Ullrich finder

Mat Trudel remediation developer

Jonatan Männchen analyst

References

github.com/...bandit/security/advisories/GHSA-q6v9-r226-v65f exploit

github.com/...bandit/security/advisories/GHSA-q6v9-r226-v65f vendor-advisory related

cna.erlef.org/cves/CVE-2026-42788.html related

osv.dev/vulnerability/EEF-CVE-2026-42788 related

github.com/...ommit/1e8e55966da9129016b73d32f0e1df4630e3b463 patch

cve.org (CVE-2026-42788)

nvd.nist.gov (CVE-2026-42788)

Download JSON