Vulnerability Description
Inefficient Algorithmic Complexity vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to exhaust server CPU via small SETTINGS or connection-level WINDOW_UPDATE frames. The attacker opens thousands of streams whose responses block on the connection send window, then sends cheap frames that each make the server walk the whole queue of blocked sends. In the reporter's run, with 3,000 blocked streams a single 9-byte SETTINGS frame took 133 ms to process. do_pending_sends/2 in lib/bandit/http2/connection.ex retries every queued send and, before each retry, removes that entry from the queue with List.delete/2, so one frame costs O(n²) list operations for n blocked streams. max_concurrent_streams defaults to :infinity, so the attacker chooses n. This issue affects bandit: from 0.3.4 before 1.14.0.
Related Weaknesses (CWE)
References
- https://cna.erlef.org/cves/CVE-2026-108529.html
- https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7
- https://github.com/mtrudel/bandit/commit/6feadb31189d18b7dcda6c663112cd3bbaf63a4
- https://github.com/mtrudel/bandit/security/advisories/GHSA-j363-h72p-296m
- https://osv.dev/vulnerability/EEF-CVE-2026-108529
FAQ
What is CVE-2026-108529?
CVE-2026-108529 is a documented vulnerability. Inefficient Algorithmic Complexity vulnerability in the HTTP/2 implementation of mtrudel bandit allows an unauthenticated remote attacker to exhaust server CPU via small SETTINGS or connection-level W...
How severe is CVE-2026-108529?
CVSS scoring is not yet available for CVE-2026-108529. Check NVD for updates.
Is there a patch for CVE-2026-108529?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.