{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-111101",
        "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "state": "PUBLISHED",
        "assignerShortName": "EEF",
        "dateReserved": "2026-10-23T12:30:01.834Z",
        "datePublished": "2026-10-26T13:31:48.184Z",
        "dateUpdated": "2026-10-26T15:35:51.401Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "collectionURL": "https://repo.hex.pm",
                    "cpes": [
                        "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "packageName": "bandit",
                    "packageURL": "pkg:hex/bandit",
                    "product": "bandit",
                    "repo": "https://github.com/mtrudel/bandit",
                    "vendor": "mtrudel",
                    "versions": [
                        {
                            "lessThan": "1.14.0",
                            "status": "affected",
                            "version": "0.1.0",
                            "versionType": "semver"
                        }
                    ]
                },
                {
                    "collectionURL": "https://github.com",
                    "cpes": [
                        "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
                    ],
                    "defaultStatus": "unaffected",
                    "packageName": "mtrudel/bandit",
                    "packageURL": "pkg:github/mtrudel/bandit",
                    "product": "bandit",
                    "repo": "https://github.com/mtrudel/bandit",
                    "vendor": "mtrudel",
                    "versions": [
                        {
                            "lessThan": "220b9dfd27f9a21305be2afc75cbe585ddc24e7a",
                            "status": "affected",
                            "version": "7201270c34b90f6c9e15c0386c2bb802c0c72ab4",
                            "versionType": "git"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "cpeMatch": [
                                {
                                    "criteria": "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*",
                                    "versionEndExcluding": "1.14.0",
                                    "versionStartIncluding": "0.1.0",
                                    "vulnerable": true
                                }
                            ],
                            "negate": false,
                            "operator": "OR"
                        }
                    ],
                    "operator": "AND"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "reporter",
                    "value": "Peter Ullrich"
                },
                {
                    "lang": "en",
                    "type": "remediation developer",
                    "value": "Mat Trudel"
                },
                {
                    "lang": "en",
                    "type": "analyst",
                    "value": "Jonatan Männchen / EEF"
                }
            ],
            "dateAssigned": "2026-10-23T12:35:54.000Z",
            "descriptions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory and CPU via a request body made of many 1-byte chunks.</p>\n<p>The chunked reader in <code>lib/bandit/http1/socket.ex</code> keeps every chunk as its own list cell and binary term until <code>IO.iodata_to_binary/1</code> joins them, and nothing limits the number of chunks. The <code>:length</code> option of <code>read_body/2</code> counts only data bytes, so tiny chunks cost far more memory than their payload: 48 MB of 1-byte chunks grew one handler process to about 500 MB and took about 6 s of CPU. The route does not need to read the body, because on keep-alive connections <code>ensure_completed/1</code> drains unread bodies through the same reader.</p>\n<p>This issue affects bandit: from 0.1.0 before 1.14.0.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory and CPU via a request body made of many 1-byte chunks.\n\nThe chunked reader in `lib/bandit/http1/socket.ex` keeps every chunk as its own list cell and binary term until `IO.iodata_to_binary/1` joins them, and nothing limits the number of chunks. The `:length` option of `read_body/2` counts only data bytes, so tiny chunks cost far more memory than their payload: 48 MB of 1-byte chunks grew one handler process to about 500 MB and took about 6 s of CPU. The route does not need to read the body, because on keep-alive connections `ensure_completed/1` drains unread bodies through the same reader.\n\nThis issue affects bandit: from 0.1.0 before 1.14.0."
                        }
                    ],
                    "value": "Allocation of Resources Without Limits or Throttling vulnerability in the HTTP/1.1 chunked body reader of mtrudel bandit allows an unauthenticated remote attacker to exhaust server memory and CPU via a request body made of many 1-byte chunks.\n\nThe chunked reader in lib/bandit/http1/socket.ex keeps every chunk as its own list cell and binary term until IO.iodata_to_binary/1 joins them, and nothing limits the number of chunks. The :length option of read_body/2 counts only data bytes, so tiny chunks cost far more memory than their payload: 48 MB of 1-byte chunks grew one handler process to about 500 MB and took about 6 s of CPU. The route does not need to read the body, because on keep-alive connections ensure_completed/1 drains unread bodies through the same reader.\n\nThis issue affects bandit: from 0.1.0 before 1.14.0."
                }
            ],
            "impacts": [
                {
                    "capecId": "CAPEC-130",
                    "descriptions": [
                        {
                            "lang": "en",
                            "supportingMedia": [
                                {
                                    "base64": false,
                                    "type": "text/html",
                                    "value": "<p>An unauthenticated client can make a single HTTP/1.1 request hold many times its body size in server memory (about 48 MB for a 1 MB body in the reporter's test), and keep CPU busy while the chunks are joined. This affects any Bandit server that accepts HTTP/1.1 requests, whether or not its routes read the body.</p>"
                                },
                                {
                                    "base64": false,
                                    "type": "text/markdown",
                                    "value": "An unauthenticated client can make a single HTTP/1.1 request hold many times its body size in server memory (about 48 MB for a 1 MB body in the reporter's test), and keep CPU busy while the chunks are joined. This affects any Bandit server that accepts HTTP/1.1 requests, whether or not its routes read the body."
                                }
                            ],
                            "value": "An unauthenticated client can make a single HTTP/1.1 request hold many times its body size in server memory (about 48 MB for a 1 MB body in the reporter's test), and keep CPU busy while the chunks are joined. This affects any Bandit server that accepts HTTP/1.1 requests, whether or not its routes read the body."
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "attackVector": "NETWORK",
                        "baseScore": 8.7,
                        "baseSeverity": "HIGH",
                        "privilegesRequired": "NONE",
                        "providerUrgency": "NOT_DEFINED",
                        "subAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "userInteraction": "NONE",
                        "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",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "HIGH",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnerabilityResponseEffort": "NOT_DEFINED"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-770",
                            "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
                "shortName": "EEF",
                "dateUpdated": "2026-10-26T13:31:48.184Z"
            },
            "references": [
                {
                    "name": "HTTP/1.1 chunked request bodies made of 1-byte chunks amplify memory use in Bandit",
                    "tags": [
                        "vendor-advisory",
                        "related"
                    ],
                    "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-jwh3-j29h-qfmw"
                },
                {
                    "name": "EEF CNA record for CVE-2026-111101",
                    "tags": [
                        "related"
                    ],
                    "url": "https://cna.erlef.org/cves/CVE-2026-111101.html"
                },
                {
                    "name": "OSV record EEF-CVE-2026-111101",
                    "tags": [
                        "related"
                    ],
                    "url": "https://osv.dev/vulnerability/EEF-CVE-2026-111101"
                },
                {
                    "name": "Introducing commit 7201270 in mtrudel/bandit",
                    "tags": [
                        "related"
                    ],
                    "url": "https://github.com/mtrudel/bandit/commit/7201270c34b90f6c9e15c0386c2bb802c0c72ab4"
                },
                {
                    "name": "Fix commit 220b9df in mtrudel/bandit",
                    "tags": [
                        "patch"
                    ],
                    "url": "https://github.com/mtrudel/bandit/commit/220b9dfd27f9a21305be2afc75cbe585ddc24e7a"
                }
            ],
            "source": {
                "discovery": "UNKNOWN"
            },
            "title": "HTTP/1.1 chunked request bodies made of 1-byte chunks amplify memory use in Bandit",
            "workarounds": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p>From 0.7.0, a server whose clients and proxies all speak HTTP/2 can disable HTTP/1 with <code>http_1_options: [enabled: false]</code>, so that the vulnerable chunked body reader never runs.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "From 0.7.0, a server whose clients and proxies all speak HTTP/2 can disable HTTP/1 with `http_1_options: [enabled: false]`, so that the vulnerable chunked body reader never runs."
                        }
                    ],
                    "value": "From 0.7.0, a server whose clients and proxies all speak HTTP/2 can disable HTTP/1 with http_1_options: [enabled: false], so that the vulnerable chunked body reader never runs."
                }
            ],
            "x_proofOfConcept": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<ol>\n<li>Run Bandit with a Plug that calls <code>Plug.Conn.read_body(conn, length: 1_000_000, read_length: 1_000_000)</code>.</li>\n<li>Send <code>POST /</code> with <code>Transfer-Encoding: chunked</code> and a body of 1,000,000 chunks of <code>1\\r\\nA\\r\\n</code>, followed by <code>0\\r\\n\\r\\n</code>.</li>\n<li>When <code>read_body</code> returns the 1,000,000 body bytes, the handler process holds about 48 MB and BEAM memory has grown by about 55 MB, for 6 MB sent.</li>\n</ol>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "1. Run Bandit with a Plug that calls `Plug.Conn.read_body(conn, length: 1_000_000, read_length: 1_000_000)`.\n2. Send `POST /` with `Transfer-Encoding: chunked` and a body of 1,000,000 chunks of `1\\r\\nA\\r\\n`, followed by `0\\r\\n\\r\\n`.\n3. When `read_body` returns the 1,000,000 body bytes, the handler process holds about 48 MB and BEAM memory has grown by about 55 MB, for 6 MB sent."
                        }
                    ],
                    "value": "* Run Bandit with a Plug that calls Plug.Conn.read_body(conn, length: 1_000_000, read_length: 1_000_000).\n* Send POST / with Transfer-Encoding: chunked and a body of 1,000,000 chunks of 1\\r\\nA\\r\\n, followed by 0\\r\\n\\r\\n.\n* When read_body returns the 1,000,000 body bytes, the handler process holds about 48 MB and BEAM memory has grown by about 55 MB, for 6 MB sent."
                }
            ],
            "x_technicalAnalysis": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "<p><strong>1. Per-chunk accumulation.</strong> <code>do_read_chunked_data!</code> in <code>lib/bandit/http1/socket.ex</code> collects chunks as <code>[body | chunk]</code>, adding a cons cell and a binary term for every chunk.</p>\n<p><strong>2. Byte-only limit.</strong> <code>:length</code> limits data bytes, not the number of chunks, so a body of <code>1\\r\\nx\\r\\n</code> chunks becomes an 8-million-element improper list before <code>IO.iodata_to_binary</code> runs. Sending 48 MB of 1-byte chunks grew the handler heap to about 500 MB and used about 6 s of CPU. The same body as one 8 MB chunk peaked at about 16 MB and took 5 ms.</p>\n<p><strong>3. No body read needed.</strong> On keep-alive connections, <code>ensure_completed/1</code> drains unread bodies through the same path. Against a Plug that never calls <code>read_body</code>, the attack used about 417 MB.</p>"
                        },
                        {
                            "base64": false,
                            "type": "text/markdown",
                            "value": "**1. Per-chunk accumulation.** `do_read_chunked_data!` in `lib/bandit/http1/socket.ex` collects chunks as `[body | chunk]`, adding a cons cell and a binary term for every chunk.\n\n**2. Byte-only limit.** `:length` limits data bytes, not the number of chunks, so a body of `1\\r\\nx\\r\\n` chunks becomes an 8-million-element improper list before `IO.iodata_to_binary` runs. Sending 48 MB of 1-byte chunks grew the handler heap to about 500 MB and used about 6 s of CPU. The same body as one 8 MB chunk peaked at about 16 MB and took 5 ms.\n\n**3. No body read needed.** On keep-alive connections, `ensure_completed/1` drains unread bodies through the same path. Against a Plug that never calls `read_body`, the attack used about 417 MB."
                        }
                    ],
                    "value": "1. Per-chunk accumulation. do_read_chunked_data! in lib/bandit/http1/socket.ex collects chunks as [body | chunk], adding a cons cell and a binary term for every chunk.\n\n2. Byte-only limit. :length limits data bytes, not the number of chunks, so a body of 1\\r\\nx\\r\\n chunks becomes an 8-million-element improper list before IO.iodata_to_binary runs. Sending 48 MB of 1-byte chunks grew the handler heap to about 500 MB and used about 6 s of CPU. The same body as one 8 MB chunk peaked at about 16 MB and took 5 ms.\n\n3. No body read needed. On keep-alive connections, ensure_completed/1 drains unread bodies through the same path. Against a Plug that never calls read_body, the attack used about 417 MB."
                }
            ]
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "id": "CVE-2026-111101",
                                "role": "CISA Coordinator",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "version": "2.0.3",
                                "timestamp": "2026-10-26T15:10:33.224480Z"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-26T15:35:51.401Z"
                }
            }
        ]
    }
}