# CVE-2026-23736: seroval Affected by Prototype Pollution via JSON Deserialization

> Attackers can achieve prototype pollution and potential code execution via malicious JSON keys in the seroval library.

- **Severity:** High 7.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jan 2026
- **Updated:** 22 Jan 2026
- **Also known as:** GHSA-hj76-42vx-jwp4

## What is CVE-2026-23736?

CVE-2026-23736 is a high-severity unsafe deserialization vulnerability in lxsmnsyc seroval, published on 21 Jan 2026. An attacker can exploit it over the internet without logging in, 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, due to improper input validation, a malicious object key can lead to prototype pollution during JSON deserialization. This vulnerability affects only JSON deserialization functionality. This issue is fixed in version 1.4.1.

Weakness: CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes)

## Which versions are affected by CVE-2026-23736?

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-2026-23736?

Upgrade seroval to 1.4.1 or later.

## Is CVE-2026-23736 being exploited?

There is no known exploitation of CVE-2026-23736 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-2026-23737](https://insights.sbomify.com/CVE-2026-23737/): seroval Affected by Remote Code Execution via JSON Deserialization (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23736 and fix it if it is affected.

What it is: CVE-2026-23736 is a high-severity unsafe deserialization vulnerability in lxsmnsyc seroval, published on 21 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-23736 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-2026-23736/ (Markdown: https://insights.sbomify.com/CVE-2026-23736/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23736
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23736
- OSV: https://osv.dev/vulnerability/CVE-2026-23736

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23736/
Summaries are generated and may contain mistakes; the official description above is the record.