SvelteKit versions from 2.49.0 through 2.53.2 (fixed in 2.53.3) contain a deserialization expansion issue in the experimental form remote function. When an application enables experimental.remoteFunctions and uses the form function to process the files array without validating files.length or individual file sizes, an attacker can submit relatively small inputs that expand into very large file arrays, leading to expensive processing and denial of service.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
sveltejs kit unaffected
Version Status Constraints
2.49.0 affected < 2.53.3
2.53.3 unaffected —

No data.

No data.

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Project Subscriptions

Vendors Products
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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/sveltejs/kit/security/advisories/GHSA-fpg4-jhqr-589c cve-icon cve-icon
https://www.vulncheck.com/advisories/sveltekit-2.49.0-before-2.53.3-denial-of-service-via-form cve-icon cve-icon
History

Fri, 28 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
Description SvelteKit versions from 2.49.0 through 2.53.2 (fixed in 2.53.3) contain a deserialization expansion issue in the experimental form remote function. When an application enables experimental.remoteFunctions and uses the form function to process the files array without validating files.length or individual file sizes, an attacker can submit relatively small inputs that expand into very large file arrays, leading to expensive processing and denial of service.
Title SvelteKit 2.49.0 before 2.53.3 Denial of Service via form
First Time appeared Svelte
Svelte kit
Weaknesses CWE-502
CPEs cpe:2.3:a:svelte:kit:*:*:*:*:*:*:*:*
Vendors & Products Svelte
Svelte kit
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-28T10:49:42.969Z

Reserved: 2026-08-28T10:39:30.356Z

Link: CVE-2026-82259

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T12:16:38.953

Modified: 2026-08-28T12:16:38.953

Link: CVE-2026-82259

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-28T13:30:07Z

Weaknesses