CVE-2026-59940CWE-502CWE-843insecure-deserialization

CVE-2026-59940

Critical · published August 18, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
56.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00812 · 56.5th percentile
Weaknesses
CWE-502 · Deserialization of Untrusted Data; CWE-843 · Access of Resource Using Incompatible Type ('Type Confusion')
Published
2026-08-18T19:16Z
References (1)
EPSS history
Timeline
  • 18 AUG 14:34Z
    Seroval: `seroval.fromJSON()` Promise resolver type confusion invokes attacker-controlled methods during deserialization
    cvelistv5