CVE-2026-82259
highpriority · track · 30EPSS 0.005 · 45 %ileUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–8.7
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
advisories (1)
Vendor and ecosystem advisories describing this.
- GHSA-fpg4-jhqr-589cSvelteKit has deserialization expansion in unvalidated `form` remote function leading to Denial of Service (experimental only)2026-02-28ghsa · osvUS
Some relatively small inputs can cause very large files arrays in `form` handlers. If the SvelteKit application code doesn't check `files.length` or individual files' sizes and performs expensive processing with them, it can result in Denial of Service. Only users with `experimental.remoteFunctions: true` who are using the `form` function and are processing the `files` array without validation are vulnerable.
sources
Which sources assert this record, and when.
references (2) nvd
External citations — patches, advisories, analysis.
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