CVE-2026-82259CWE-502insecure-deserialization

CVE-2026-82259

High · published August 28, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
44.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
8.7 · 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
EPSS
0.00533 · 44.2th percentile
Weakness
CWE-502 · Deserialization of Untrusted Data
Published
2026-08-28T16:16Z
Affected products (1)
ProductVersionsFixed in
svelte/sveltekit≥ 2.49.0, < 2.53.32.53.3
References (2)
https://github.com/sveltejs/kit/security/advisories/GHSA-fpg4-jhqr-589c · [email protected]https://www.vulncheck.com/advisories/sveltekit-2.49.0-before-2.53.3-denial-of-service-via-form · [email protected]
EPSS history
Timeline
  • 30 AUG 16:19Z
    EPSS moved — → 0%
    epss
  • 28 AUG 10:49Z
    SvelteKit 2.49.0 before 2.53.3 Denial of Service via form
    cvelistv5