EEF-CVE-2026-42786
- Source
- https://cna.erlef.org/osv/EEF-CVE-2026-42786.html
- Import Source
- https://cna.erlef.org/osv/EEF-CVE-2026-42786.json
- JSON Data
- https://api.osv.dev/v1/vulns/EEF-CVE-2026-42786
- Aliases
-
- CVE-2026-42786
- GHSA-pf94-94m9-536p
- Published
- 2026-05-01T20:34:17.014Z
- Modified
- 2026-05-02T04:17:26.677Z
- Severity
-
- 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
- Summary
- WebSocket fragmented message reassembly unbounded in bandit
- Details
-
Summary
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':handleframe/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 maxframe_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.
Configuration
The application must accept WebSocket connections. Applications that expose no WebSocket endpoints are not affected.
- Database specific
{ "cpe_ids": [ "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*" ], "capec_ids": [ "CAPEC-130" ], "cwe_ids": [ "CWE-770" ] }- References
- Credits
-
-
- Peter Ullrich - FINDER
-
- Mat Trudel - REMEDIATION_DEVELOPER
-
- Jonatan Männchen - ANALYST
-
Affected packages
Hex / bandit
Package
- Name
- bandit
- Purl
- pkg:hex/bandit