CVE-2026-22803
Published: 15 January 2026
Summary
CVE-2026-22803 is a high-severity Memory Allocation with Excessive Size Value (CWE-789) vulnerability in Svelte Kit. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 5.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct mapping to application exploitation causing endpoint DoS via memory exhaustion in a web framework.
NVD 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…
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server to allocate a large amount of memory, causing DoS via memory exhaustion. This vulnerability is fixed in 2.49.5.
Deeper analysisAI
CVE-2026-22803 is a denial-of-service vulnerability in SvelteKit, a framework for building robust web applications using Svelte. It affects versions 2.49.0 through 2.49.4, where the experimental form remote function processes submitted form data in a binary format. A specially crafted payload can cause the server to allocate an excessive amount of memory, leading to memory exhaustion and service disruption. The issue is linked to CWE-789 (Uncontrolled Memory Allocation) and CWE-770 (Allocation of Resources Without Limits or Throttling), with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
An unauthenticated attacker with network access can exploit this vulnerability by submitting a malicious payload to the affected form remote function endpoint. The attack requires low complexity and no user interaction, allowing remote exploitation over the network. Successful attacks result in high-impact availability impairment through server memory exhaustion, with no impact on confidentiality or integrity.
Mitigation is provided in SvelteKit version 2.49.5, which addresses the memory allocation flaw. Relevant resources include the fixing commit at https://github.com/sveltejs/kit/commit/8ed8155215b9a74012fecffb942ad9a793b274e5, the @sveltejs/adapter-node release at https://github.com/sveltejs/kit/releases/tag/@sveltejs%2Fadapter-node@5.5.1, and the security advisory at https://github.com/sveltejs/kit/security/advisories/GHSA-j2f3-wq62-6q46. Affected deployments should upgrade promptly to the patched version.
Details
- CWE(s)