FKIE_CVE-2026-55407

Vulnerability from fkie_nvd - Published: 2026-07-16 17:16 - Updated: 2026-10-24 20:10
Severity
6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Summary
Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decode_unknown_field function in buffa's protobuf decoder allocated heap memory in proportion to untrusted input (unknown fields in the serialized protobuf) without enforcing an allocation budget, affecting any message decoded from untrusted input using code generated with preserve_unknown_fields=true (the default); a small, well-formed payload of nested unknown fields inside a StartGroup could trigger roughly 22x memory amplification (for example a 64 MiB input forcing about 1.4 GB of heap allocation), and length-delimited unknown fields could be sized arbitrarily, so an unauthenticated attacker could crash a process through memory exhaustion because the top-level message size cap did not account for in-decode amplification. This issue is fixed in version 0.8.0.
References
security-advisories@github.comhttps://github.com/anthropics/buffa/commit/278fa43fcff661d4ee6bd83b75955a153d4281fc
security-advisories@github.comhttps://github.com/anthropics/buffa/pull/184
security-advisories@github.comhttps://github.com/anthropics/buffa/releases/tag/v0.8.0
security-advisories@github.comhttps://github.com/anthropics/buffa/security/advisories/GHSA-f9qc-qg88-7pq5
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "buffa",
          "vendor": "anthropics",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.8.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decode_unknown_field function in buffa\u0027s protobuf decoder allocated heap memory in proportion to untrusted input (unknown fields in the serialized protobuf) without enforcing an allocation budget, affecting any message decoded from untrusted input using code generated with preserve_unknown_fields=true (the default); a small, well-formed payload of nested unknown fields inside a StartGroup could trigger roughly 22x memory amplification (for example a 64 MiB input forcing about 1.4 GB of heap allocation), and length-delimited unknown fields could be sized arbitrarily, so an unauthenticated attacker could crash a process through memory exhaustion because the top-level message size cap did not account for in-decode amplification. This issue is fixed in version 0.8.0."
    },
    {
      "lang": "es",
      "value": "Buffa es una implementaci\u00f3n pura en Rust de Protocol Buffers con soporte de primera clase para ediciones de protobuf. Antes de la versi\u00f3n 0.8.0, la funci\u00f3n \u201cdecode_unknown_field\u201d en el decodificador de protobuf de Buffa asignaba memoria del mont\u00f3n en proporci\u00f3n a la entrada no confiable (campos desconocidos en el protobuf serializado) sin aplicar un presupuesto de asignaci\u00f3n, afectando cualquier mensaje decodificado de entrada no confiable usando c\u00f3digo generado con \u201cpreserve_unknown_fields=true\u201d (el valor predeterminado); una carga \u00fatil peque\u00f1a y bien formada de campos desconocidos anidados dentro de un \u201cStartGroup\u201d podr\u00eda desencadenar aproximadamente una amplificaci\u00f3n de memoria de 22x (por ejemplo, una entrada de 64 MiB forzando aproximadamente 1.4 GB de asignaci\u00f3n de memoria del mont\u00f3n), y los campos desconocidos delimitados por longitud podr\u00edan tener un tama\u00f1o arbitrario, por lo que un atacante no autenticado podr\u00eda bloquear un proceso por agotamiento de memoria porque el l\u00edmite de tama\u00f1o del mensaje de nivel superior no ten\u00eda en cuenta la amplificaci\u00f3n durante la decodificaci\u00f3n. Este problema est\u00e1 solucionado en la versi\u00f3n 0.8.0."
    }
  ],
  "id": "CVE-2026-55407",
  "lastModified": "2026-10-24T20:10:00.137",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "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:P/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55407",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-16T18:03:55.427453Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-16T17:16:57.770",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/anthropics/buffa/commit/278fa43fcff661d4ee6bd83b75955a153d4281fc"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/anthropics/buffa/pull/184"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/anthropics/buffa/releases/tag/v0.8.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/anthropics/buffa/security/advisories/GHSA-f9qc-qg88-7pq5"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        },
        {
          "lang": "en",
          "value": "CWE-770"
        },
        {
          "lang": "en",
          "value": "CWE-789"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



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