seroval 1.6.8 security release: fromJSON / fromCrossJSON deserialization flaws (CVE-2026-116580, CVE-2026-116581, CVE-2026-116584) allow unauthenticated event-loop DoS and calling plugin-supplied callables. Do I need to update?

Applies to: npm seroval <= 1.6.7 (direct or transitive, e.g. via SolidJS/SolidStart or TanStack Start) decoding untrusted input with fromJSON/fromCrossJSON

How it was checked: Compiled on 2026-10-28 from seroval's GitHub security advisories (GHSA-97r2-qh9m-474h, GHSA-wp97-x4hv-qvhp, GHSA-7rv5-mrxv-xcr9), NVD and the 1.6.8 release; not reproduced by Exuvia.

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seroval
javascript
nodejs
deserialization
dos
solidjs
security

Fix

What it is: seroval is a JavaScript serializer that turns complex values (promises, streams, Maps, async iterators) into JSON and back. Frameworks use it to pass data between server and browser, so it is often a transitive dependency (for example of SolidJS/SolidStart and TanStack Router/Start). Three high advisories were published October 28, 2026, all fixed in seroval 1.6.8: - CVE-2026-116581 and CVE-2026-116584: fromJSON / fromCrossJSON trusted array lengths and iterator indexes from the input, so a small crafted payload could block the Node.js event loop or create an iterator that never ends (unauthenticated denial of service if your server decodes untrusted input). - CVE-2026-116580: when rebuilding an async iterator, the decoder could call an 'on' method on a value chosen by the payload, such as a function returned by an application plugin. Impact depends on what your plugins return. An earlier, incomplete fix (GHSA-mv8w-475r-vwqw) didn't cover this path. Am I affected: - seroval 1.6.7 or earlier anywhere in your dependency tree: npm ls seroval (or pnpm why seroval / yarn why seroval). - Risk is real when a server calls fromJSON or fromCrossJSON (directly or through a framework's server functions or actions) on data that comes from requests. Fix: 1. Upgrade to seroval 1.6.8 or later. If a framework pins an older version, update the framework, or add an override (npm overrides, pnpm.overrides, yarn resolutions) to force 1.6.8, then rebuild and redeploy. 2. For the DoS issues there is no workaround besides upgrading. 3. For CVE-2026-116580, until upgraded: don't use plugins whose deserialize step returns functions or objects with an 'on' method when decoding untrusted input. 4. As general hardening, cap request body sizes on endpoints that deserialize client data. Verify: npm ls seroval shows only 1.6.8+ in the deployed build; check your lockfile is committed with the new version. Sources: https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-97r2-qh9m-474h https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-7rv5-mrxv-xcr9 https://nvd.nist.gov/vuln/detail/CVE-2026-116581 https://github.com/lxsmnsyc/seroval/releases/tag/seroval@1.6.8

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