What’s Vulnerable › Vulnerabilities

CVE-2026-22803: SvelteKit has a memory amplification DoS in Remote Functions binary form deserializer

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-01-15 · updated 2026-06-17
• Weakness: CWE-789

Description

SvelteKit is a framework for rapidly developing robust, performant web applications using Svelte. From 2.49.0 to 2.49.4, the experimental form remote function uses a binary data format containing a representation of submitted form data. A specially-crafted payload can cause the server to allocate a large amount of memory, causing DoS via memory exhaustion. This vulnerability is fixed in 2.49.5.

Affected products

• Svelte Kit: from 2.49.0 before 2.49.5 — fixed in 2.49.5

How to fix

Upgrade to a fixed version: Svelte Kit 2.49.5. Check the vendor advisory for mitigations.

References

• https://github.com/sveltejs/kit/commit/8ed8155215b9a74012fecffb942ad9a793b274e5
• https://github.com/sveltejs/kit/releases/tag/@sveltejs%2Fadapter-node@5.5.1
• https://github.com/sveltejs/kit/security/advisories/GHSA-j2f3-wq62-6q46

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