TI-2026-42747 Aliases CVE-2026-59940 GHSA-mv8w-475r-vwqw

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

MEDIUM 50CWE-502Published 2026-08-18 · Updated 2026-08-18

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-502.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00812 57th percentileScored 2026-11-07

Fix Fixed seroval (lxsmnsyc): 1.5.3seroval (npm): 1.5.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
lxsmnsyc	seroval	before 1.5.3	1.5.3	Patch available	CNA
—	seroval (npm)	before 1.5.3	1.5.3	Patch available	GHSA-mv8w-475r-vwqw

seroval Vendorlxsmnsyc Affected before 1.5.3 Fixed in 1.5.3 Patch available CNA
seroval (npm) Vendor— Affected before 1.5.3 Fixed in 1.5.3 Patch available GHSA-mv8w-475r-vwqw

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:lxsmnsyc:seroval::::::::	—	—	lxsmnsyc

cpe:2.3:a:lxsmnsyc:seroval:*:*:*:*:*:*:*:* Versions — — ·lxsmnsyc

Remediation

Fix · CNA seroval (lxsmnsyc) Fixed in 1.5.3
Fix · GHSA-mv8w-475r-vwqw seroval (npm) Fixed in 1.5.3 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Critical. Red Hat's page for this CVE →

Not affected: 1 product

Ansible Automation Orchestrator 2026

Timeline

2026-10-02 Threatist record created from CVE-2026-59940
2026-10-03 Alias added: GHSA-mv8w-475r-vwqw
2026-10-31 Affected versions changed · Red Hat

References

Other 3

TI-2026-66132 Seroval: `fromJSON()` Promise thenable assimilation invokes plugin-produced callables (bypass of CVE-2026-59940) CVSS 3.1CRITICAL 9.8
TI-2026-19109 seroval Affected by Prototype Pollution via JSON Deserialization CVSS 3.1CRITICAL 9.8
TI-2026-19298 seroval affected by Denial of Service via RegExp serialization CVSS 3.1HIGH 7.5
TI-2026-80920 Denial of service in Seroval fromJSON via unvalidated array length CVSS 3.1HIGH 7.5
TI-2026-80917 Seroval fromJSON deserializer hangs on crafted sequence, causing DoS CVSS 3.1HIGH 7.5
TI-2026-66131 Seroval: Memory exhaustion via unchecked TypedArray length in JSON deserialization CVSS 3.1HIGH 7.5

See all 12 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences