← Back to CVE Explorer

CVE-2026-110676

Full vulnerability record from the local CVENow database.

Description

Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum. With allow_bignum, a JSON number with a fraction or exponent decodes to a Math::BigFloat, which stores the exponent separately and so decodes cheaply. Encoding it untyped or as JSON_TYPE_FLOAT writes the plain decimal form with one digit per unit of exponent. Nothing bounds the exponent, so the 12-byte text [1e30000000] encodes to 30 MB. Untrusted JSON decoded with allow_bignum and encoded again can exhaust memory and CPU.

Severity
HIGH
CVSS score
7.5 (v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
9b29abf9-4ab0-4765-b253-1875cd9b441e
Published
2026-10-19 19:17:21.320000
Last modified
2026-10-29 17:17:59.987000
View original CVE JSON
{
  "id": "CVE-2026-110676",
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
  "published": "2026-10-19T19:17:21.320",
  "lastModified": "2026-10-29T17:17:59.987",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum.\n\nWith allow_bignum, a JSON number with a fraction or exponent decodes to a Math::BigFloat, which stores the exponent separately and so decodes cheaply. Encoding it untyped or as JSON_TYPE_FLOAT writes the plain decimal form with one digit per unit of exponent. Nothing bounds the exponent, so the 12-byte text [1e30000000] encodes to 30 MB.\n\nUntrusted JSON decoded with allow_bignum and encoded again can exhaust memory and CPU."
    }
  ],
  "affected": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "collectionURL": "https://cpan.org/modules",
          "packageName": "Cpanel-JSON-XS",
          "modules": [
            "Cpanel::JSON::XS"
          ],
          "programFiles": [
            "XS.xs"
          ],
          "programRoutines": [
            {
              "name": "encode_rv"
            },
            {
              "name": "encode_sv"
            }
          ],
          "repo": "https://github.com/rurban/Cpanel-JSON-XS",
          "packageURL": "pkg:cpan/Cpanel-JSON-XS",
          "versions": [
            {
              "version": "0",
              "lessThan": "4.80",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-29T16:41:22.938408Z",
          "id": "CVE-2026-110676",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-405"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/rurban/Cpanel-JSON-XS/commit/996ab96972b967a917536d291947b5f3cf42e960.patch",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    },
    {
      "url": "https://metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.80/changes",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    }
  ]
}