The internal island renderer endpoint (/__nuxt_island/...) decodes and hashes attacker-controlled request input before it validates the URL-resident hash. An unauthenticated POST /__nuxt_island/<name>_<anything>.json with a large JSON body (for example ~4.6 MB / 150k keys) is fully read, destr-parsed, and run through ohash before the request is rejected with a 400. Because Nitro runs on a single event loop, this both wastes CPU on the doomed request and delays every concurrent request. A low request rate is enough to degrade or stall the server. No valid hash and no authentication are required.
Fixed in nuxt@4.5.1 and nuxt@3.21.10. The island handler now enforces a raw body-size cap (413) and a JSON nesting-depth cap (400) before parsing or hashing, so oversized or deeply nested input is rejected cheaply.
Put a small request-body limit in front of /__nuxt_island/ at your reverse proxy / edge (islands legitimately send only a compact props payload), or disable server components if unused.
{
"nvd_published_at": null,
"severity": "HIGH",
"github_reviewed": true,
"github_reviewed_at": "2026-08-05T21:43:03Z",
"cwe_ids": [
"CWE-407",
"CWE-770"
]
}