CVE-2026-104635

Status: DeferredHigh (8.2)—

Uncontrolled Recursion vulnerability in Protobuf.JSON.Decode in elixir-protobuf protobuf allows an unauthenticated remote attacker to crash the decoding process via a deeply nested JSON document. Any application that decodes attacker-supplied JSON with Protobuf.JSON.decode/3, Protobuf.JSON.decode!/3, or Protobuf.JSON.from_decoded/3 into a schema that contains a self-referential or cyclic message type is affected.

In lib/protobuf/json/decode.ex, the embedded-message clause of decode_singular/3 recurses into internal_from_json_data/3 once per nesting level without incrementing or checking the decoder's depth counter.

Read full descriptionShow less

The depth guard increase_depth_and_maybe_throw/1 covers only the Google.Protobuf.ListValue and Google.Protobuf.Struct clauses, so the recursion_limit option has no effect on user-defined message types. Each nesting level allocates a stack frame and heap objects, and a sufficiently deep document exhausts the memory of the decoding process. Confidentiality and integrity are not affected.

This issue affects protobuf: from 0.8.0 before 0.17.1.

CVSS

Version: 4.0
Vector: CVSS:4.0/AV:N/AC:L/AT:P/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
Base score: 8.2

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.39%
Percentile among all scored CVEs: 31
Score date: 10/14/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access85 %
Primary impactT1499.004 Application or System Exploitationimpact90 %

Vulnerabilidad de recursión no controlada en servicio de decodificación JSON expuesto en red sin autenticación (AV:N, PR:N, UI:N). Permite DoS por agotamiento de memoria mediante documento JSON anidado profundamente.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Filter Network Traffic Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Application Isolation and Sandboxing

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Elixir-protobuf — Protobuf^AI

CWEs

CWE-674

References

Raw JSON (NVD)

Show

{
  "id": "CVE-2026-104635",
  "cveTags": [],
  "metrics": {
    "cvssMetricV40": [
      {
        "type": "Secondary",
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "cvssData": {
          "Safety": "NOT_DEFINED",
          "version": "4.0",
          "Recovery": "NOT_DEFINED",
          "baseScore": 8.2,
          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/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",
          "exploitMaturity": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "NONE",
          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "confidentialityRequirement": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
        }
      }
    ]
  },
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:elixir-protobuf:protobuf:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/elixir-protobuf/protobuf",
          "vendor": "elixir-protobuf",
          "modules": [
            "'Elixir.Protobuf.JSON.Decode'",
            "'Elixir.Protobuf.JSON'"
          ],
          "product": "protobuf",
          "versions": [
            {
              "status": "affected",
              "version": "0.8.0",
              "lessThan": "0.17.1",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:hex/protobuf",
          "packageName": "protobuf",
          "programFiles": [
            "lib/protobuf/json/decode.ex",
            "lib/protobuf/json.ex"
          ],
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "'Elixir.Protobuf.JSON.Decode':from_json_data/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON.Decode':decode_singular/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':decode/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':decode!/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':from_decoded/3"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:elixir-protobuf:protobuf:*:*:*:*:*:*:*:*"
          ],
          "repo": "https://github.com/elixir-protobuf/protobuf",
          "vendor": "elixir-protobuf",
          "modules": [
            "'Elixir.Protobuf.JSON.Decode'",
            "'Elixir.Protobuf.JSON'"
          ],
          "product": "protobuf",
          "versions": [
            {
              "status": "affected",
              "version": "b0a1d4eaffaf50012fa71a8e931a47cf252d0370",
              "lessThan": "e9432ad1c4099511905353cebcececa3a1f7c3ff",
              "versionType": "git"
            }
          ],
          "packageURL": "pkg:github/elixir-protobuf/protobuf",
          "packageName": "elixir-protobuf/protobuf",
          "programFiles": [
            "lib/protobuf/json/decode.ex",
            "lib/protobuf/json.ex"
          ],
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "'Elixir.Protobuf.JSON.Decode':from_json_data/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON.Decode':decode_singular/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':decode/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':decode!/3"
            },
            {
              "name": "'Elixir.Protobuf.JSON':from_decoded/3"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-10-09T09:17:07.360",
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-104635.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-protobuf/protobuf/commit/b0a1d4eaffaf50012fa71a8e931a47cf252d0370",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-protobuf/protobuf/commit/e9432ad1c4099511905353cebcececa3a1f7c3ff",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/elixir-protobuf/protobuf/security/advisories/GHSA-m497-c2h9-rvw6",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-104635",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "description": [
        {
          "lang": "en",
          "value": "CWE-674"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Uncontrolled Recursion vulnerability in Protobuf.JSON.Decode in elixir-protobuf protobuf allows an unauthenticated remote attacker to crash the decoding process via a deeply nested JSON document. Any application that decodes attacker-supplied JSON with Protobuf.JSON.decode/3, Protobuf.JSON.decode!/3, or Protobuf.JSON.from_decoded/3 into a schema that contains a self-referential or cyclic message type is affected.\n\nIn lib/protobuf/json/decode.ex, the embedded-message clause of decode_singular/3 recurses into internal_from_json_data/3 once per nesting level without incrementing or checking the decoder's depth counter. The depth guard increase_depth_and_maybe_throw/1 covers only the Google.Protobuf.ListValue and Google.Protobuf.Struct clauses, so the recursion_limit option has no effect on user-defined message types. Each nesting level allocates a stack frame and heap objects, and a sufficiently deep document exhausts the memory of the decoding process. Confidentiality and integrity are not affected.\n\nThis issue affects protobuf: from 0.8.0 before 0.17.1."
    }
  ],
  "lastModified": "2026-10-09T17:07:31.693",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
}