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HTTP/2 WINDOW_UPDATE and SETTINGS frames reset the request body read timeout in Bandit

Type: advisorySources: Official CVE List

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.

Products
bandit
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-115269
Confirmed fixed CVEs
Not specified
Updated in this feed
30 Oct 2026, 12:02 UTC · Revision 1

Source evidence

HTTP/2 WINDOW_UPDATE and SETTINGS frames reset the request body read timeout in Bandit

core-cve · Original source

Published 26 Oct 2026, 13:30 UTC

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.

cve:CVE-2026-115269

bandit

Fixed versions: Not specified

bandit

Fixed versions: Not specified

Complete source record
{
  "id": "23f41b5a712d78171c6caddd988605ce6f1c5cb4ee06cbf997362388cbd250c5",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-115269",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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 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.",
    "evidence": "cve:CVE-2026-115269",
    "products": [
      {
        "name": {
          "value": "bandit",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      },
      {
        "name": {
          "value": "bandit",
          "evidence": "/containers/cna/affected/1/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-115269",
      "aliases": [
        "CVE-2026-115269"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "Safety": "NOT_DEFINED",
            "version": "4.0",
            "Recovery": "NOT_DEFINED",
            "baseScore": 8.7,
            "Automatable": "NOT_DEFINED",
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "providerUrgency": "NOT_DEFINED",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
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      ],
      "affected": [
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          "cpes": [
            "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/mtrudel/bandit",
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          "versions": [
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              "version": "1.4.0",
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          ],
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          "packageName": "bandit",
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          "vendor": "mtrudel",
          "product": "bandit",
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              "lessThan": "220b9dfd27f9a21305be2afc75cbe585ddc24e7a",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/mtrudel/bandit",
          "packageName": "mtrudel/bandit",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T15:35:52.079Z",
      "provider": "cve",
      "references": [
        "https://github.com/mtrudel/bandit/security/advisories/GHSA-p2qv-vx88-385x",
        "https://cna.erlef.org/cves/CVE-2026-115269.html",
        "https://osv.dev/vulnerability/EEF-CVE-2026-115269",
        "https://github.com/mtrudel/bandit/commit/fff06efe3be962b484bd4d3eb339372fda5a231f",
        "https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-115269",
                    "role": "CISA Coordinator",
                    "options": [
                      {
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                      },
                      {
                        "Automatable": "yes"
                      },
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                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T15:02:19.174445Z"
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            "providerMetadata": {
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        ],
        "cna": {
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          "shortName": "EEF",
          "dateUpdated": "2026-10-26T13:30:24.621Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-115269",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 316056,
  "published_at": "2026-10-26T13:30:24.621+00:00"
}