CVE-2026-59940

Critical

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.

SeverityCritical
CVSS9.8
Exploit probability—
ProductSeroval
PublishedAug 18, 2026
First seenAug 18, 2026

How to fix

Update
  • seroval1.5.3 or later

Affected products

ProductAffected versionsFixed in
serovalnpmv < 1.5.31.5.3

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