CVE-2026-82259Network attack vectorHinoki check available

Denial of service via expanding file arrays

Published Aug 28, 2026 · Updated Aug 28, 2026

Deserialization expansion in SvelteKit 2.49.0 through 2.53.2 allows remote attackers to interrupt service via crafted form data. The experimental form remote function expands relatively small inputs into very large files arrays, and application processing then consumes excessive resources. Exposure requires remoteFunctions to be enabled and a form handler to process the files array without validating its length or individual file sizes.

CVSS severity8.7
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Deserialization expansion in SvelteKit 2.49.0 through 2.53.2 allows remote attackers to interrupt service via crafted form data. The experimental form remote function expands relatively small inputs into very large files arrays, and application processing then consumes excessive resources. Exposure requires remoteFunctions to be enabled and a form handler to process the files array without validating its length or individual file sizes.

The record

CVE
CVE-2026-82259
Published
Aug 28, 2026
Updated
Aug 28, 2026
Vendor
Svelte
Product
SvelteKit
Classifications
CWE-502, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.49.0 <2.53.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Svelte · SvelteKitversion=2.49.0 <2.53.3

Published CVSS scores

7.5TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8TenableAV:N/AC:L/Au:N/C:N/I:N/A:C
8.7TenableCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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