Vulnerability-Lookup

GHSA-9PQ4-5HCF-288C

Vulnerability from github – Published: 2026-02-19 15:18 – Updated: 2026-02-19 15:18

Summary

Cache poisoning in @sveltejs/adapter-vercel

Details

Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users.

Successful exploitation requires a victim to visit an attacker-controlled link while authenticated.

Existing deployments are protected by Vercel's WAF, but users should upgrade as soon as possible.

Severity ?

5.3 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@sveltejs/adapter-vercel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.3.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-27118"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-02-19T15:18:02Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "Versions of `@sveltejs/adapter-vercel` prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users.\n\nSuccessful exploitation requires a victim to visit an attacker-controlled link while authenticated.\n\nExisting deployments are protected by Vercel\u0027s WAF, but users should upgrade as soon as possible.",
  "id": "GHSA-9pq4-5hcf-288c",
  "modified": "2026-02-19T15:18:02Z",
  "published": "2026-02-19T15:18:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/kit/security/advisories/GHSA-9pq4-5hcf-288c"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sveltejs/kit"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Cache poisoning in @sveltejs/adapter-vercel"
}

CVE-2026-27118 (GCVE-0-2026-27118)

Vulnerability from cvelistv5 – Published: 2026-02-20 21:24 – Updated: 2026-02-20 21:24

Title

Cache poisoning in @sveltejs/adapter-vercel

Summary

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users. Successful exploitation requires a victim to visit an attacker-controlled link while authenticated. Existing deployments are protected by Vercel's WAF, but users should upgrade as soon as possible. This vulnerability is fixed in 6.3.2.

Severity ?

5.3 (Medium)


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

CWE

CWE-346 - Origin Validation Error

Assigner

GitHub_M

References

URL

Tags

https://github.com/sveltejs/kit/security/advisori…

x_refsource_CONFIRM

Impacted products

	Vendor	Product	Version
	sveltejs	kit	Affected: < 6.3.2

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "kit",
          "vendor": "sveltejs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.3.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. Versions of @sveltejs/adapter-vercel prior to 6.3.2 are vulnerable to cache poisoning. An internal query parameter intended for Incremental Static Regeneration (ISR) is accessible on all routes, allowing an attacker to cause sensitive user-specific responses to be cached and served to other users. Successful exploitation requires a victim to visit an attacker-controlled link while authenticated. Existing deployments are protected by Vercel\u0027s WAF, but users should upgrade as soon as possible. This vulnerability is fixed in 6.3.2."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "PASSIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-346",
              "description": "CWE-346: Origin Validation Error",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-20T21:24:55.577Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sveltejs/kit/security/advisories/GHSA-9pq4-5hcf-288c",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sveltejs/kit/security/advisories/GHSA-9pq4-5hcf-288c"
        }
      ],
      "source": {
        "advisory": "GHSA-9pq4-5hcf-288c",
        "discovery": "UNKNOWN"
      },
      "title": "Cache poisoning in @sveltejs/adapter-vercel"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27118",
    "datePublished": "2026-02-20T21:24:55.577Z",
    "dateReserved": "2026-02-17T18:42:27.043Z",
    "dateUpdated": "2026-02-20T21:24:55.577Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-9PQ4-5HCF-288C

CVE-2026-27118 (GCVE-0-2026-27118)

Tags

Sightings

Nomenclature