# CVE-2026-104845: Seroval unbound TypedArray allocation in deserialization

Source: https://junglewise.ai/threats/cve-2026-104845-seroval-facilitates-js-value-stringification-including-complex  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-02. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-104845 · Severity: high · CVSS 7.5 · Published 2026-10-02

Seroval is a JavaScript library that serializes and deserializes complex data structures beyond standard JSON capabilities. An attacker who can provide untrusted JSON input can craft a malicious object with an inflated array size that causes the library to allocate massive amounts of memory or CPU, freezing the application and denying service to legitimate users. This affects any application using Seroval to deserialize untrusted data from the network or user input.

Technologies: [Lxsmnsyc Seroval](https://junglewise.ai/threats/technologies/lxsmnsyc-seroval), [seroval (npm)](https://junglewise.ai/threats/technologies/seroval). Vendors: [Lxsmnsyc](https://junglewise.ai/threats/vendors/lxsmnsyc), [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-104845 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104845 being exploited in the wild.

**How severe is CVE-2026-104845?** High severity, with a CVSS score of 7.5, published 2 October 2026.

**Which products and versions are affected?** Lxsmnsyc Seroval before 1.6.3; seroval (npm) <= 1.6.2, SEMVER:introduced=0,fixed=1.6.3.

**Is there a fix for CVE-2026-104845?** Yes. seroval (npm): upgrade to 1.6.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-104845 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-104845?** Check whether you run Lxsmnsyc 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 1.6.3 or later

  ```sh
  npm install seroval@1.6.3
  ```


## Technical details

The deserializeTypedArray function in fromJSON and fromCrossJSON fails to validate the element count of serialized TypedArray structures, trusting a source value as an ArrayBuffer without checking byteLength. An attacker provides a small JSON object with a large length field, causing the TypedArray constructor to synchronously allocate the specified number of elements, exhausting memory or CPU and starving the event loop. The offset validation does not catch this because source.byteLength is undefined in the crafted input.

## Affected products

- lxsmnsyc Seroval before 1.6.3

## Identifiers

- CVE-2026-104845
- GHSA-jp82-f5mq-hwhp

## Timeline

- 2026-10-02: disclosed
- 2026-10-02: patched

## References

- [https://github.com/lxsmnsyc/seroval/commit/ac0163e420ac7dcbbefac4d069bcefad300a4851](https://github.com/lxsmnsyc/seroval/commit/ac0163e420ac7dcbbefac4d069bcefad300a4851)
- [https://github.com/lxsmnsyc/seroval/commit/e54a6f62784b9e48e3a5fa2ab4089ca69fb8996e](https://github.com/lxsmnsyc/seroval/commit/e54a6f62784b9e48e3a5fa2ab4089ca69fb8996e)

## 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 incomplete fix for AsyncIterator deserialization bypass](https://junglewise.ai/threats/cve-2026-116580-seroval-facilitates-javascript-value-stringification-including)