HTTP/2 blocked-send deadlines reset on every WINDOW_UPDATE, letting a trickle pin stream processes indefinitely in Bandit

{
  "id": "520d38c8a663abe652c605d2c75ffdeb8d399c0e0d054281d41f0cbc30176037",
  "url": "https://osv.dev/vulnerability/CVE-2026-105659",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "HTTP/2 blocked-send deadlines reset on every WINDOW_UPDATE, letting a trickle pin stream processes indefinitely in Bandit",
    "summary": "Uncontrolled Resource Consumption vulnerability in mtrudel bandit allows an unauthenticated remote attacker to pin HTTP/2 stream processes indefinitely via a trickle of small WINDOW_UPDATE frames. A stream whose response outruns the connection or stream send window blocks until the peer grants more window, and each block carries a 15 second deadline. Both deadlines restart whenever the peer makes partial progress. Bandit.HTTP2.Connection.finish_data/5 re-queues a partially advanced send in pending_sends with a fresh expires_at, so every WINDOW_UPDATE on stream 0, and every SETTINGS frame, resets the clock. Bandit.HTTP2.Stream.send_data/3 recurses on each stream WINDOW_UPDATE and re-arms a fresh after read_timeout. A peer that grants a few bytes every few seconds keeps the blocked stream process, its Plug state and any resource it holds mid-response alive for as long as it keeps dripping, and repeats this across streams and connections to exhaust server processes and memory. The two paths are independent. The stream-level block is reached on its own by widening the connection window with a large WINDOW_UPDATE on stream 0 and shrinking the per-stream window with a small SETTINGS_INITIAL_WINDOW_SIZE, so closing only the connection-level path leaves it exploitable. This issue affects bandit: from 1.4.0 before 1.13.0.",
    "evidence": "osv:CVE-2026-105659",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-105659",
      "aliases": [
        "CVE-2026-105659",
        "EEF-CVE-2026-105659",
        "GHSA-69m6-wcv4-rwcf"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mtrudel/bandit",
              "type": "GIT",
              "events": [
                {
                  "introduced": "fff06efe3be962b484bd4d3eb339372fda5a231f"
                },
                {
                  "fixed": "d88b21953c65061f21136ea76a89a4f95a2ac7a1"
                },
                {
                  "introduced": "e5d4262b07b3e1026c57647b281dccfababea13b"
                },
                {
                  "fixed": "d6daa4a950604a9bc91b49da785747cff370ca66"
                },
                {
                  "fixed": "fff06efe3be962b484bd4d3eb339372fda5a231f"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "fff06efe3be962b484bd4d3eb339372fda5a231f"
                      },
                      {
                        "fixed": "d88b21953c65061f21136ea76a89a4f95a2ac7a1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "1.4.0"
                      },
                      {
                        "fixed": "1.13.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "fff06efe3be962b484bd4d3eb339372fda5a231f"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d88b21953c65061f21136ea76a89a4f95a2ac7a1"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.12.5",
            "1.12.4",
            "1.12.3",
            "1.12.1",
            "1.12.0",
            "1.11.1",
            "1.11.0",
            "1.10.4",
            "1.10.3",
            "1.10.2",
            "1.10.1",
            "1.10.0",
            "1.9.0",
            "1.8.0",
            "1.7.0",
            "1.6.11",
            "1.6.10",
            "1.6.9",
            "1.6.8",
            "1.6.7",
            "1.6.6",
            "1.6.5",
            "1.6.4",
            "1.6.3",
            "1.6.2",
            "1.6.1",
            "1.6.0",
            "1.5.7",
            "1.5.6",
            "1.5.5",
            "1.5.4",
            "1.5.3",
            "1.5.2",
            "1.5.1",
            "1.5.0",
            "1.4.2",
            "1.4.1",
            "1.4.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-105659.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:40.149902480Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-105659.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-105659",
        "https://repo.hex.pm",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105659.json",
        "https://github.com/mtrudel/bandit/security/advisories/GHSA-69m6-wcv4-rwcf",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-105659",
        "https://github.com/mtrudel/bandit/commit/d88b21953c65061f21136ea76a89a4f95a2ac7a1",
        "https://github.com/mtrudel/bandit/commit/fff06efe3be962b484bd4d3eb339372fda5a231f",
        "https://github.com/mtrudel/bandit"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105659.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-105659",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507772,
  "published_at": "2026-10-14T16:54:46.484+00:00"
}