---
id: CVE-2026-115269
title: >-
  HTTP/2 WINDOW_UPDATE and SETTINGS frames reset the request body read timeout
  in Bandit
summary: >-
  Allocation of Resources Without Limits or Throttling vulnerability in the
  HTTP/2 request body reader of mtrudel bandit allows an unauthenticated remote
  attacker to hold stream processes open indefinitely via WINDOW_UPDATE or empty
  SETTIN…
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-835
  - CWE-770
vendor: mtrudel
product: bandit
affected:
  - bandit >= 1.4.0 < 1.14.0
  - >-
    mtrudel/bandit >= fff06efe3be962b484bd4d3eb339372fda5a231f <
    220b9dfd27f9a21305be2afc75cbe585ddc24e7a
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-26T15:02:19.174445Z'
published: '2026-10-26'
updated: '2026-10-26'
sourceUpdated: '2026-10-26T15:35:52.079Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115269'
references:
  - url: 'https://github.com/mtrudel/bandit/security/advisories/GHSA-p2qv-vx88-385x'
    label: >-
      HTTP/2 WINDOW_UPDATE and SETTINGS frames reset the request body read
      timeout in Bandit
  - url: 'https://cna.erlef.org/cves/CVE-2026-115269.html'
    label: EEF CNA record for CVE-2026-115269
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-115269'
    label: OSV record EEF-CVE-2026-115269
  - url: >-
      https://github.com/mtrudel/bandit/commit/fff06efe3be962b484bd4d3eb339372fda5a231f
    label: Introducing commit fff06ef in mtrudel/bandit
  - url: >-
      https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a
    label: Fix commit 220b9df in mtrudel/bandit
tags:
  - cve.org
ingestedAt: '2026-10-26T14:27:31.822Z'
---

## Overview

Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/2 request body reader of mtrudel bandit allows an unauthenticated remote attacker to hold stream processes open indefinitely via WINDOW_UPDATE or empty SETTINGS frames sent while a Plug reads the request body.

Bandit.HTTP2.Stream.do_read_data/4 in lib/bandit/http2/stream.ex waits for each frame with a fresh read_timeout. A stream WINDOW_UPDATE, or the zero-delta window update that every empty SETTINGS frame delivers to all streams, ends the wait without delivering any body data, and the loop starts a new full countdown. A client that sends one of these 9-byte frames before each countdown expires keeps read_body blocked, together with the stream process and whatever the application holds while reading, for as long as it likes.

This issue affects bandit: from 1.4.0 before 1.14.0.

## Affected

- `bandit >= 1.4.0 < 1.14.0`
- `mtrudel/bandit >= fff06efe3be962b484bd4d3eb339372fda5a231f < 220b9dfd27f9a21305be2afc75cbe585ddc24e7a`

## Remediation

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

### Workarounds

Disable HTTP/2 with http_2_options: [enabled: false], so that the vulnerable read path never runs.