Vulnerability-Lookup

GHSA-CRPF-4HRX-3JRP

Vulnerability from github – Published: 2026-02-19 20:28 – Updated: 2026-02-23 22:23

Summary

Svelte SSR attribute spreading includes inherited properties from prototype chain

Details

In server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.

Severity

5.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N

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JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.51.4"
      },
      "package": {
        "ecosystem": "npm",
        "name": "svelte"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.51.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27125"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-915"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-19T20:28:49Z",
    "nvd_published_at": "2026-02-20T23:16:02Z",
    "severity": "MODERATE"
  },
  "details": "In server-side rendering, attribute spreading on elements (e.g. `\u003cdiv {...attrs}\u003e`) enumerates inherited properties from the object\u0027s prototype chain rather than only own properties. In environments where `Object.prototype` has already been polluted \u2014 a precondition outside of Svelte\u0027s control \u2014 this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected.",
  "id": "GHSA-crpf-4hrx-3jrp",
  "modified": "2026-02-23T22:23:50Z",
  "published": "2026-02-19T20:28:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27125"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sveltejs/svelte"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/svelte/releases/tag/svelte@5.51.5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Svelte SSR attribute spreading includes inherited properties from prototype chain"
}

CVE-2026-27125 (GCVE-0-2026-27125)

Vulnerability from cvelistv5 – Published: 2026-02-20 22:29 – Updated: 2026-02-25 21:33

Title

Svelte SSR attribute spreading includes inherited properties from prototype chain

Summary

svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.

Severity

5.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-02-25 21:33 UTC

CWE

CWE-915 - Improperly Controlled Modification of Dynamically-Determined Object Attributes

Assigner

GitHub_M mitre root Scorecard

References

3 references

URL	Tags
https://github.com/sveltejs/svelte/security/advis…	x_refsource_CONFIRM
https://github.com/sveltejs/svelte/commit/73098bb…	x_refsource_MISC
https://github.com/sveltejs/svelte/releases/tag/s…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
sveltejs	svelte	Affected: < 5.51.5

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-27125",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-25T21:33:01.018593Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-25T21:33:14.822Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "svelte",
          "vendor": "sveltejs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.51.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. \u003cdiv {...attrs}\u003e) enumerates inherited properties from the object\u0027s prototype chain rather than only own properties. In environments where Object.prototype has already been polluted \u2014 a precondition outside of Svelte\u0027s control \u2014 this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-915",
              "description": "CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-20T22:29:45.364Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sveltejs/svelte/security/advisories/GHSA-crpf-4hrx-3jrp"
        },
        {
          "name": "https://github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sveltejs/svelte/commit/73098bb26c6f06e7fd1b0746d817d2c5ee90755f"
        },
        {
          "name": "https://github.com/sveltejs/svelte/releases/tag/svelte@5.51.5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sveltejs/svelte/releases/tag/svelte@5.51.5"
        }
      ],
      "source": {
        "advisory": "GHSA-crpf-4hrx-3jrp",
        "discovery": "UNKNOWN"
      },
      "title": "Svelte SSR attribute spreading includes inherited properties from prototype chain"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27125",
    "datePublished": "2026-02-20T22:29:45.364Z",
    "dateReserved": "2026-02-17T18:42:27.043Z",
    "dateUpdated": "2026-02-25T21:33:14.822Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-CRPF-4HRX-3JRP

CVE-2026-27125 (GCVE-0-2026-27125)

Tags

Sightings

Nomenclature

Related by attack behaviour