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SvelteKit CVE-2026-82261

| EUVDEUVD-2026-67587 HIGH
Uncontrolled Resource Consumption (CWE-400)
2026-08-28 VulnCheck GHSA-xjpx-7387-jh7h
8.7
CVSS 4.0 · Vendor: VulnCheck
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Severity by source

Vendor (VulnCheck) PRIMARY
8.7 HIGH
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
7.5 HIGH

Network vector confirmed; PR:N because no authentication gates the form endpoint; A:H for complete availability loss; no confidentiality or integrity impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

4
Patch available
Aug 28, 2026 - 13:17 EUVD
Source Code Evidence Fetched
Aug 28, 2026 - 12:04 vuln.today
Analysis Generated
Aug 28, 2026 - 12:04 vuln.today
CVE Published
Aug 28, 2026 - 10:49 cve.org
HIGH 8.7

DescriptionCVE.org

SvelteKit (@sveltejs/kit) versions >=2.49.0 and <=2.52.1 with experimental remote functions and form enabled contain a CPU exhaustion vulnerability in form deserialization. An attacker can send malformed form data to cause the server to become unresponsive while processing the request, resulting in denial of service. Fixed in 2.52.2.

AnalysisAI

CPU exhaustion in SvelteKit's experimental remote form deserialization endpoint allows unauthenticated remote attackers to render affected servers unresponsive by submitting malformed form data, resulting in denial of service. Versions 2.49.0 through 2.52.1 of @sveltejs/kit are affected, but only when both the experimental.remoteFunctions and form features are simultaneously enabled - a non-default, opt-in configuration. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
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Delivery
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Exploit
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Execution
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Impact
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Vulnerability AssessmentAI

Exploitation Exploitation requires that the target SvelteKit application has explicitly enabled BOTH experimental.remoteFunctions (an opt-in flag in the SvelteKit config) AND the form feature within that experimental context - neither is enabled by default. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H) scores 8.7, indicating unauthenticated network-exploitable denial of service with no attack complexity - calibrated as if the vulnerable endpoint is reachable. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation The primary fix is upgrading @sveltejs/kit to version 2.52.2 or later, which resolves the unbounded CPU consumption in the form deserialization path (upstream patch commit: https://github.com/sveltejs/kit/commit/3e607b314aec9e5f278d32847945b8b6323e1cb8). … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, identify all production SvelteKit instances with experimental.remoteFunctions and form features simultaneously enabled and document affected applications for urgent remediation. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

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CVE-2026-82261 vulnerability details – vuln.today

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