CVE-2026-59940

Seroval: `seroval.fromJSON()` Promise resolver type confusion invokes attacker-controlled methods during deserialization

State: Published
Severity: 9.8 Critical
Published: Aug 18, 2026
Updated: Aug 18, 2026
Reserved: Jul 7, 2026

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Description

Seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.5.3, seroval.fromJSON() allows attacker-controlled JSON Promise control nodes to operate on values from the general deserialization reference table without verifying genuine internal Promise resolver records, causing deserialization side effects with plugins enabled and potentially unintended server-side invocation or remote code execution when downstream frameworks register callable wrappers. This issue is fixed in version 1.5.3.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-502 Deserialization of Untrusted Data
CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')

Affected Products

Product	Versions
serovallxsmnsyc	< 1.5.3Affected

References

https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-mv8w-475r-vwqw

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