CVE-2026-123568

Description

Sveltejs devalue before 5.6.3 contains a prototype pollution vulnerability that allows attackers to alter object prototypes by supplying untrusted data to uneval. When the generated code is later evaluated, it creates objects with polluted prototypes, producing output data whose shape differs from the original input.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: LOW
CVSS score: 2.1 / 10
CVSS vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Effective score: 2.1 / 10 LOW source: CNA overview
CWE(s): CWE-1321
Reserved: 2026-11-06
Published: 2026-11-08 01:38 UTC
Last updated: 2026-11-08 01:38 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/123xxx/CVE-2026-123568.json

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-119453

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Affected products (1)

Vendor	Product	Versions	Platforms
sveltejs	devalue	`0` (affected), `5.6.3` (unaffected)	—

Vendor references (2)

References embedded in the original CVE record by the assigning CNA.

GitHub Security Advisory (GHSA-8qm3-746x-r74r) vendor-advisory
VulnCheck Advisory: Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-123568.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/devalue",
          "product": "devalue",
          "vendor": "sveltejs",
          "versions": [
            {
              "lessThan": "5.6.3",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.6.3",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:svelte:devalue:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.6.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "elliott-with-the-longest-name-on-github"
        }
      ],
      "datePublic": "2026-02-18T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Sveltejs devalue before 5.6.3 contains a prototype pollution vulnerability that allows attackers to alter object prototypes by supplying untrusted data to uneval. When the generated code is later evaluated, it creates objects with polluted prototypes, producing output data whose shape differs from the original input."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 2.1,
            "baseSeverity": "LOW",
            "privilegesRequired": "HIGH",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-1321",
              "description": "Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-08T01:38:06.526Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-8qm3-746x-r74r)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/sveltejs/devalue/security/advisories/GHSA-8qm3-746x-r74r"
        },
        {
          "name": "VulnCheck Advisory: Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.6.3-prototype-pollution-via-uneval-output"
        }
      ],
      "title": "Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123568",
    "datePublished": "2026-11-08T01:38:06.526Z",
    "dateReserved": "2026-11-06T00:53:14.312Z",
    "dateUpdated": "2026-11-08T01:38:06.526Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}