CVE-2026-58226

Full vulnerability record from the local CVENow database.

Description

Inefficient Algorithmic Complexity vulnerability in elixir-mint hpax allows unauthenticated denial-of-service via unbounded HPACK integer decoding. hpax decodes HPACK variable-length integers with no upper bound on the decoded value or the number of continuation octets. 'Elixir.HPAX.Types':decode_remaining_integer/3 accumulates the integer as int + (value <<< m), shifting by 7 more bits for each continuation octet and stopping only on a terminating octet or truncated input, never because the integer grew too large. Because BEAM integers are arbitrary precision, a run of N continuation octets builds an O(N)-bit bignum and re-adds into an ever-larger bignum on each step, so the total decoding cost is superlinear (about O(N^2)). An unauthenticated attacker who can send an HTTP/2 header block to a server using this decoder (reached through the 'Elixir.HPAX':decode/2 entry point) can supply a small header block that forces a large, attacker-controlled amount of CPU (and transient memory), a denial-of-service amplification. This issue affects hpax from 0.1.1 before 1.0.4.

Severity

HIGH

CVSS score

8.7 (v4.0)

Vulnerability status

Deferred

Source identifier

6b3ad84c-e1a6-4bf7-a703-f496b71e49db

Published

2026-07-06 11:16:31.143000

Last modified

2026-10-25 20:10:00.147000

View original CVE JSON

{
  "id": "CVE-2026-58226",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-07-06T11:16:31.143",
  "lastModified": "2026-10-25T20:10:00.147",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Inefficient Algorithmic Complexity vulnerability in elixir-mint hpax allows unauthenticated denial-of-service via unbounded HPACK integer decoding.\n\nhpax decodes HPACK variable-length integers with no upper bound on the decoded value or the number of continuation octets. 'Elixir.HPAX.Types':decode_remaining_integer/3 accumulates the integer as int + (value <<< m), shifting by 7 more bits for each continuation octet and stopping only on a terminating octet or truncated input, never because the integer grew too large. Because BEAM integers are arbitrary precision, a run of N continuation octets builds an O(N)-bit bignum and re-adds into an ever-larger bignum on each step, so the total decoding cost is superlinear (about O(N^2)). An unauthenticated attacker who can send an HTTP/2 header block to a server using this decoder (reached through the 'Elixir.HPAX':decode/2 entry point) can supply a small header block that forces a large, attacker-controlled amount of CPU (and transient memory), a denial-of-service amplification.\n\nThis issue affects hpax from 0.1.1 before 1.0.4."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de complejidad algorítmica ineficiente en elixir-mint hpax permite una denegación de servicio no autenticada a través de la decodificación de enteros HPACK sin límites.\n\nhpax decodifica enteros HPACK de longitud variable sin un límite superior en el valor decodificado o en el número de octetos de continuación. ’Elixir.HPAX.Types’:decode_remaining_integer/3 acumula el entero como int + (value <<< m), desplazando 7 bits más por cada octeto de continuación y deteniéndose solo en un octeto de terminación o entrada truncada, nunca porque el entero se hizo demasiado grande. Debido a que los enteros BEAM son de precisión arbitraria, una secuencia de N octetos de continuación construye un bignum de O(N) bits y se vuelve a añadir a un bignum cada vez más grande en cada paso, por lo que el costo total de decodificación es superlineal (aproximadamente O(N^2)). Un atacante no autenticado que puede enviar un bloque de encabezado HTTP/2 a un servidor que utiliza este decodificador (alcanzado a través del punto de entrada ’Elixir.HPAX’:decode/2) puede proporcionar un pequeño bloque de encabezado que fuerza una gran cantidad de CPU (y memoria transitoria) controlada por el atacante, una amplificación de denegación de servicio.\n\nEste problema afecta a hpax desde la versión 0.1.1 anterior a la 1.0.4."
    }
  ],
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "vendor": "elixir-mint",
          "product": "hpax",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.hex.pm",
          "packageName": "hpax",
          "cpes": [
            "cpe:2.3:a:elixir-mint:hpax:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "Elixir.HPAX",
            "Elixir.HPAX.Types"
          ],
          "programFiles": [
            "lib/hpax.ex",
            "lib/hpax/types.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.HPAX':decode/2"
            },
            {
              "name": "'Elixir.HPAX.Types':decode_integer/2"
            },
            {
              "name": "'Elixir.HPAX.Types':decode_remaining_integer/3"
            }
          ],
          "repo": "https://github.com/elixir-mint/hpax",
          "packageURL": "pkg:hex/hpax",
          "versions": [
            {
              "version": "0.1.1",
              "lessThan": "1.0.4",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "elixir-mint",
          "product": "hpax",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com",
          "packageName": "elixir-mint/hpax",
          "cpes": [
            "cpe:2.3:a:elixir-mint:hpax:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "Elixir.HPAX",
            "Elixir.HPAX.Types"
          ],
          "programFiles": [
            "lib/hpax.ex",
            "lib/hpax/types.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.HPAX':decode/2"
            },
            {
              "name": "'Elixir.HPAX.Types':decode_integer/2"
            },
            {
              "name": "'Elixir.HPAX.Types':decode_remaining_integer/3"
            }
          ],
          "repo": "https://github.com/elixir-mint/hpax",
          "packageURL": "pkg:github/elixir-mint/hpax",
          "versions": [
            {
              "version": "56db437a7e2c515e3bdd770ac7947b02cd2390d0",
              "lessThan": "1ba4bb2dc91e80089cf89c73970ac3ded76f17eb",
              "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:H/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": 8.7,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "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": "2026-07-06T12:49:38.954923Z",
          "id": "CVE-2026-58226",
          "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-407"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-58226.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-mint/hpax/commit/1ba4bb2dc91e80089cf89c73970ac3ded76f17eb",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-mint/hpax/security/advisories/GHSA-jj2p-32j7-whj2",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-58226",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-mint/hpax/security/advisories/GHSA-jj2p-32j7-whj2",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}