[ CVE-2026-104846 · Published 2 Oct 2026 ]
Seroval: `fromJSON()` Promise thenable assimilation invokes plugin-produced callables (bypass of GHSA-mv8w-475r-vwqw)
[ Why it matters ]Priority signals
- Critical severity: CVSS 9.8
[ Description ]Official description
Seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. From 0.12.0 until 1.6.2, fromJSON deserialization of a fulfilled Promise control node can pass a plugin-produced callable-bearing thenable to a native Promise resolver. ECMAScript thenable assimilation then invokes the callable unexpectedly, allowing attacker-controlled JSON to trigger code in applications using plugin-capable Seroval releases. This path bypasses the Promise resolver type-confusion remediation in version 1.5.3 for CVE-2026-59940 because the unexpected invocation occurs through native Promise settlement after the referenced value is deserialized. This issue is fixed in version 1.6.2.
[ Fixes ]Fixes and patches
- seroval 1.6.2Fixed version · GitHub Advisories · npm package seroval: upgrade to 1.6.2 or later (affected >= 0.12.0, <= 1.6.0)
[ Packages ]Affected open-source packages
- seroval npmAffected >= 0.12.0, <= 1.6.0 · fixed in 1.6.2 · GHSA-p6vx-979v-rg4c