Critical 9.8Published Oct 2, 2026

CVE-2026-104846Seroval: `fromJSON()` Promise thenable assimilation invokes plugin-produced callables (bypass of CVE-2026-59940)

Updated under an hour ago (2026-10-19 07:30 UTC)

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It affects lxsmnsyc seroval. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.34%, higher than 26% of scored CVEs.

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Every CVE for lxsmnsyc seroval

Exploited in the last 30 days

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.

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-843
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.34% (percentile 26)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

lxsmnsyc seroval lxsmnsyc:seroval (from the name)	from 0.12.0, < 1.6.2	CNA record

References

https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-p6vx-979v-rg4cx-refsource-confirm
https://github.com/lxsmnsyc/seroval/commit/f1ffcc96d259f9b5b3d71feb262b58240c90e7b7x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.