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CVE-2026-42788

Full vulnerability record from the local CVENow database.

Description

Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated memory exhaustion via oversized HTTP/2 frames. 'Elixir.Bandit.HTTP2.Frame':deserialize/2 in lib/bandit/http2/frame.ex checks the SETTINGS_MAX_FRAME_SIZE limit only after pattern-matching payload::binary-size(length), which requires the entire frame body to be present in memory before either the accept or reject clause can fire. A peer that announces a frame length up to the 24-bit maximum (~16 MiB) causes the server to buffer that entire body before the size guard is evaluated, regardless of the max_frame_size negotiated during the HTTP/2 handshake (default 16 KiB per RFC 9113). An unauthenticated attacker holding many concurrent connections can force the server to buffer far more memory than the negotiated frame size limit should permit, leading to memory pressure and potential denial of service. This issue affects bandit: from 0.3.6 before 1.11.0.

Severity
MEDIUM
CVSS score
6.9 (v4.0)
Vulnerability status
Deferred
Source identifier
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Published
2026-05-01 21:16:17.500000
Last modified
2026-10-26 20:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2026-42788",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-05-01T21:16:17.500",
  "lastModified": "2026-10-26T20:10:00.160",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated memory exhaustion via oversized HTTP/2 frames.\n\n'Elixir.Bandit.HTTP2.Frame':deserialize/2 in lib/bandit/http2/frame.ex checks the SETTINGS_MAX_FRAME_SIZE limit only after pattern-matching payload::binary-size(length), which requires the entire frame body to be present in memory before either the accept or reject clause can fire. A peer that announces a frame length up to the 24-bit maximum (~16 MiB) causes the server to buffer that entire body before the size guard is evaluated, regardless of the max_frame_size negotiated during the HTTP/2 handshake (default 16 KiB per RFC 9113).\n\nAn unauthenticated attacker holding many concurrent connections can force the server to buffer far more memory than the negotiated frame size limit should permit, leading to memory pressure and potential denial of service.\n\nThis issue affects bandit: from 0.3.6 before 1.11.0."
    },
    {
      "lang": "es",
      "value": "Vulnerabilidad de asignación de recursos sin límites o estrangulamiento en mtrudel bandit permite el agotamiento de memoria no autenticado a través de tramas HTTP/2 sobredimensionadas.\n\n’Elixir.Bandit.HTTP2.Frame’:deserialize/2 en lib/bandit/http2/frame.ex verifica el límite SETTINGS_MAX_FRAME_SIZE solo después de la coincidencia de patrones payload::binary-size(length), lo que requiere que todo el cuerpo de la trama esté presente en memoria antes de que se pueda activar la cláusula de aceptación o rechazo. Un par que anuncia una longitud de trama de hasta el máximo de 24 bits (~16 MiB) hace que el servidor almacene en búfer todo ese cuerpo antes de que se evalúe la protección de tamaño, independientemente del max_frame_size negociado durante el handshake de HTTP/2 (16 KiB por defecto según RFC 9113).\n\nUn atacante no autenticado que mantiene muchas conexiones concurrentes puede forzar al servidor a almacenar en búfer mucha más memoria de lo que debería permitir el límite de tamaño de trama negociado, lo que lleva a una presión de memoria y una potencial denegación de servicio.\n\nEste problema afecta a bandit: desde 0.3.6 antes de 1.11.0."
    }
  ],
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "vendor": "mtrudel",
          "product": "bandit",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.hex.pm",
          "packageName": "bandit",
          "cpes": [
            "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Bandit.HTTP2.Frame'"
          ],
          "programFiles": [
            "lib/bandit/http2/frame.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Bandit.HTTP2.Frame':deserialize/2"
            }
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "packageURL": "pkg:hex/bandit",
          "versions": [
            {
              "version": "0.3.6",
              "lessThan": "1.11.0",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "mtrudel",
          "product": "bandit",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com",
          "packageName": "mtrudel/bandit",
          "cpes": [
            "cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Bandit.HTTP2.Frame'"
          ],
          "programFiles": [
            "lib/bandit/http2/frame.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Bandit.HTTP2.Frame':deserialize/2"
            }
          ],
          "repo": "https://github.com/mtrudel/bandit",
          "packageURL": "pkg:github/mtrudel/bandit",
          "versions": [
            {
              "version": "f00dd69a5b2a4863be585907acd853c4ffd41399",
              "lessThan": "1e8e55966da9129016b73d32f0e1df4630e3b463",
              "versionType": "git",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 6.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "LOW",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-05-02T01:14:16.975049Z",
          "id": "CVE-2026-42788",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-770"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-42788.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/mtrudel/bandit/commit/1e8e55966da9129016b73d32f0e1df4630e3b463",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-q6v9-r226-v65f",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-42788",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-q6v9-r226-v65f",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}