# CVE-2026-23737: seroval Affected by Remote Code Execution via JSON Deserialization

> Attackers can execute arbitrary JavaScript code by exploiting improper input handling in the seroval library's JSON deserialization functions.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jan 2026
- **Updated:** 22 Jan 2026
- **Also known as:** GHSA-3rxj-6cgf-8cfw

## What is CVE-2026-23737?

CVE-2026-23737 is a high-severity unsafe deserialization vulnerability in lxsmnsyc seroval, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 1.4.0 and below, improper input handling in the JSON deserialization component can lead to arbitrary JavaScript code execution. Exploitation is possible via overriding constant value and error deserialization, allowing indirect access to unsafe JS evaluation. At minimum, attackers need the ability to perform 4 separate requests on the same function, and partial knowledge of how the serialized data is used during later runtime processing. This vulnerability affects the fromJSON and fromCrossJSON functions in a client-to-server transmission scenario. This issue has been fixed in version 1.4.0.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-23737?

2 open source packages ship an affected version, including seroval. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `seroval` | npm | All versions | 1.4.1 |
| `seroval` | npm | All versions | 1.4.1 |

Products: Lxsmnsyc Seroval.

## How do I fix CVE-2026-23737?

Upgrade seroval to 1.4.1 or later.

## Is CVE-2026-23737 being exploited?

There is no known exploitation of CVE-2026-23737 in the wild and no public exploit code.

## Other vulnerabilities in lxsmnsyc seroval

- [CVE-2026-23956](https://insights.sbomify.com/CVE-2026-23956/): seroval affected by Denial of Service via RegExp serialization (high 7.5)
- [CVE-2026-23957](https://insights.sbomify.com/CVE-2026-23957/): seroval is vulnerable to Denial of Service via array serialization (high 7.5)
- [CVE-2026-24006](https://insights.sbomify.com/CVE-2026-24006/): Seroval affected by Denial of Service via Deeply Nested Objects (high 7.5)
- [CVE-2026-23736](https://insights.sbomify.com/CVE-2026-23736/): seroval Affected by Prototype Pollution via JSON Deserialization (high 7.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23737 and fix it if it is affected.

What it is: CVE-2026-23737 is a high-severity unsafe deserialization vulnerability in lxsmnsyc seroval, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23737 in the wild and no public exploit code.

Affected packages and fixed versions:
- seroval (npm): affected all versions; fixed in 1.4.1
- seroval (npm): affected all versions; fixed in 1.4.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-23737/ (Markdown: https://insights.sbomify.com/CVE-2026-23737/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23737
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23737
- OSV: https://osv.dev/vulnerability/CVE-2026-23737

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23737/
Summaries are generated and may contain mistakes; the official description above is the record.