Vulnerability · Published Jan 22, 2026 · Assigned by GitHub_M

CVE-2026-23956seroval affected by Denial of Service via RegExp serialization

High 7.5

In plain English

A high-severity regular-expression denial of service in seroval from lxsmnsyc. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 54.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 0.2.0 through 1.4.0, overriding RegExp serialization with extremely large patterns can exhaust JavaScript runtime memory during deserialization. Additionally, overriding RegExp serialization with patterns that trigger catastrophic backtracking can lead to ReDoS (Regular Expression Denial of Service). This issue has been fixed in version 1.4.1.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	seroval	1.4.1	GHSA-hx9m-jf43-8ffr

Affected products (as reported)

Vendor	Product	Versions
lxsmnsyc	seroval	>= 0.2.0, < 1.4.1

Weakness: CWE-1333 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-hx9m-jf43-8ffr x_refsource_CONFIRM
https://github.com/lxsmnsyc/seroval/commit/ce9408ebc87312fcad345a73c172212f2a798060 x_refsource_MISC
https://github.com/lxsmnsyc/seroval/blob/v0.2.0/packages/seroval/src/index.ts#L90 x_refsource_MISC