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GHSA-QGF5-7GF3-JG2G

Vulnerability from github – Published: 2026-10-19 21:36 – Updated: 2026-10-19 21:36

Details

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.

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-110676"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-405"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-19T19:17:21Z",
    "severity": null
  },
  "details": "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.",
  "id": "GHSA-qgf5-7gf3-jg2g",
  "modified": "2026-10-19T21:36:28Z",
  "published": "2026-10-19T21:36:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-110676"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rurban/Cpanel-JSON-XS/commit/996ab96972b967a917536d291947b5f3cf42e960.patch"
    },
    {
      "type": "WEB",
      "url": "https://metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.80/changes"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-110676 (GCVE-0-2026-110676)

Vulnerability from cvelistv5 – Published: 2026-10-19 18:11 – Updated: 2026-10-19 18:11

Title

Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum

Summary

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

No CVSS data available.

CWE

CWE-405 - Asymmetric Resource Consumption (Amplification)

Assigner

CPANSec CNA under the redhat root

CNA scorecard C 63/100 over 296 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/rurban/Cpanel-JSON-XS/commit/9…	patch
https://metacpan.org/release/RURBAN/Cpanel-JSON-X…	release-notes

Impacted products

1 product

Vendor	Product	Version
		Affected: 0 , < 4.80 (custom)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "modules": [
            "Cpanel::JSON::XS"
          ],
          "packageName": "Cpanel-JSON-XS",
          "packageURL": "pkg:cpan/Cpanel-JSON-XS",
          "programFiles": [
            "XS.xs"
          ],
          "programRoutines": [
            {
              "name": "encode_rv"
            },
            {
              "name": "encode_sv"
            }
          ],
          "repo": "https://github.com/rurban/Cpanel-JSON-XS",
          "versions": [
            {
              "lessThan": "4.80",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-405",
              "description": "CWE-405 Asymmetric Resource Consumption (Amplification)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T18:11:45.805Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/rurban/Cpanel-JSON-XS/commit/996ab96972b967a917536d291947b5f3cf42e960.patch"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.80/changes"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Upgrade to Cpanel-JSON-XS 4.80 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "timeline": [
        {
          "lang": "en",
          "time": "2026-10-14T00:00:00.000Z",
          "value": "Version 4.80 released with fix."
        }
      ],
      "title": "Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2026-110676",
    "datePublished": "2026-10-19T18:11:45.805Z",
    "dateReserved": "2026-10-14T13:23:56.248Z",
    "dateUpdated": "2026-10-19T18:11:45.805Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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