---
id: CVE-2026-108525
title: >-
  HTTP/2 inbound flow control is not enforced, letting a client queue unbounded
  DATA in stream processes in Bandit
summary: >-
  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.…
severity: high
cvss: 8.7
cvssVector: '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'
cvssSource: cna
cwe:
  - CWE-770
vendor: mtrudel
product: bandit
affected:
  - bandit >= 0.3.1 < 1.14.0
  - >-
    mtrudel/bandit >= c8dc1e97050cf359f61ed6cdd110f3cdaf1d6f5f <
    220b9dfd27f9a21305be2afc75cbe585ddc24e7a
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-26T15:04:12.110479Z'
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T15:35:52.227Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-108525'
references:
  - url: 'https://github.com/mtrudel/bandit/security/advisories/GHSA-c3g7-2pg5-qvwh'
    label: >-
      HTTP/2 inbound flow control is not enforced, letting a client queue
      unbounded DATA in stream processes in Bandit
  - url: 'https://cna.erlef.org/cves/CVE-2026-108525.html'
    label: EEF CNA record for CVE-2026-108525
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-108525'
    label: OSV record EEF-CVE-2026-108525
  - url: >-
      https://github.com/mtrudel/bandit/commit/c8dc1e97050cf359f61ed6cdd110f3cdaf1d6f5f
    label: Introducing commit c8dc1e9 in mtrudel/bandit
  - url: >-
      https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a
    label: Fix commit 220b9df in mtrudel/bandit
tags:
  - cve.org
ingestedAt: '2026-10-26T14:27:31.821Z'
---

## Overview

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.

## Affected

- `bandit >= 0.3.1 < 1.14.0`
- `mtrudel/bandit >= c8dc1e97050cf359f61ed6cdd110f3cdaf1d6f5f < 220b9dfd27f9a21305be2afc75cbe585ddc24e7a`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

### Workarounds

From 0.7.0, disable HTTP/2 with http_2_options: [enabled: false], which removes the vulnerable path.