# CVE-2026-116580: Seroval incomplete fix for AsyncIterator deserialization bypass

Source: https://junglewise.ai/threats/cve-2026-116580-seroval-facilitates-javascript-value-stringification-including  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-116580 · Severity: high · CVSS 7.3 · Published 2026-10-26

Seroval is a JavaScript serialization library that handles complex data structures. A flaw in the fromJSON deserializer allows attackers to forge stream or sequence objects with untrusted input, potentially executing arbitrary code through application plugins. This is an incomplete patch of a prior vulnerability, and the impact depends on what the application exposes.

Technologies: [seroval (npm)](https://junglewise.ai/threats/technologies/seroval). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-116580 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116580 being exploited in the wild.

**How severe is CVE-2026-116580?** High severity, with a CVSS score of 7.3, published 26 October 2026.

**Which products and versions are affected?** Alexis Munsayac Seroval before 1.6.8; seroval (npm) <= 1.6.7, SEMVER:introduced=0,fixed=1.6.8.

**Is there a fix for CVE-2026-116580?** Yes. seroval (npm): upgrade to 1.6.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116580 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-116580?** Check whether you run Alexis Munsayac Seroval or seroval (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- seroval (npm): upgrade to 1.6.8 or later

  ```sh
  npm install seroval@1.6.8
  ```


## Technical details

The vulnerability is an incomplete fix (CVE-2026-59940) where fromJSON rebuilds AsyncIteratorFactoryInstance by calling source.on(listener) without validating that source is a genuine internal stream. An attacker can reuse identifier slots in untrusted Seroval input to pass a malicious callable or object with an on method, triggering plugin-supplied code. The fix in 1.6.8 now uses instanceof checks and real classes instead of marker properties to prevent identity spoofing.

## Affected products

- Alexis Munsayac Seroval before 1.6.8

## Identifiers

- CVE-2026-116580
- GHSA-7rv5-mrxv-xcr9

## Timeline

- 2026-10-26: disclosed

## References

- [https://github.com/lxsmnsyc/seroval/commit/3edc78b495ea0d6bd498143e5b3e56996607c5f2](https://github.com/lxsmnsyc/seroval/commit/3edc78b495ea0d6bd498143e5b3e56996607c5f2)
- [https://github.com/lxsmnsyc/seroval/commit/50926b3ee198fb757e6ce3aa70efeed38d931c8d](https://github.com/lxsmnsyc/seroval/commit/50926b3ee198fb757e6ce3aa70efeed38d931c8d)

## Related threats

- [Seroval denial of service via array-like object in deserialization](https://junglewise.ai/threats/cve-2026-116584-seroval-facilitates-javascript-value-stringification-including)
- [Seroval typed array constructor name injection](https://junglewise.ai/threats/cve-2026-116583-seroval-facilitates-javascript-value-stringification-including)
- [Seroval JavaScript RegExp code injection in HTML script elements](https://junglewise.ai/threats/cve-2026-116582-seroval-facilitates-javascript-value-stringification-including)
- [Seroval improper sequence node validation in deserialization](https://junglewise.ai/threats/cve-2026-116581-seroval-facilitates-javascript-value-stringification-including)
- [Seroval Promise thenable code execution via fromJSON deserialization](https://junglewise.ai/threats/cve-2026-104846-seroval-facilitates-js-value-stringification-including-complex)