# CVE-2023-28103: Prototype pollution in matrix-react-sdk

> Remote servers can cause prototype pollution in matrix-react-sdk, leading to denial of service and logic errors in specific configurations.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Mar 2023
- **Updated:** 18 Feb 2025
- **Also known as:** CLEANSTART-2024-LQ80354, GHSA-6g43-88cp-w5gv

## What is CVE-2023-28103?

CVE-2023-28103 is a high-severity vulnerability in matrix-org matrix-react-sdk, published on 28 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

matrix-react-sdk is a Matrix chat protocol SDK for React Javascript. In certain configurations, data sent by remote servers containing special strings in key locations could cause modifications of the `Object.prototype`, disrupting matrix-react-sdk functionality, causing denial of service and potentially affecting program logic. This is fixed in matrix-react-sdk 3.69.0 and users are advised to upgrade. There are no known workarounds for this vulnerability. Note this advisory is distinct from GHSA-2x9c-qwgf-94xr which refers to a similar issue.

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

## Which versions are affected by CVE-2023-28103?

2 open source packages ship an affected version, including matrix-react-sdk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `matrix-react-sdk` | npm | All versions | 3.69.0 |
| `matrix-react-sdk` | npm | All versions | 3.69.0 |

Products: Matrix-React-Sdk Project Matrix-React-Sdk.

## How do I fix CVE-2023-28103?

Upgrade matrix-react-sdk to 3.69.0 or later.

## Is CVE-2023-28103 being exploited?

There is no known exploitation of CVE-2023-28103 in the wild and no public exploit code.

## Other vulnerabilities in matrix-org matrix-react-sdk

- [CVE-2023-37259](https://insights.sbomify.com/CVE-2023-37259/): Cross site scripting in Export Chat feature (medium 6.1)
- [CVE-2023-30609](https://insights.sbomify.com/CVE-2023-30609/): matrix-react-sdk vulnerable to HTML injection in search results via plaintext message highlighting (medium 5.4)
- [CVE-2021-32622](https://insights.sbomify.com/CVE-2021-32622/): File upload local preview can run embedded scripts after user interaction (medium 4.2)
- [CVE-2021-21320](https://insights.sbomify.com/CVE-2021-21320/): User content sandbox can be confused into opening arbitrary documents (low 2.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28103 and fix it if it is affected.

What it is: CVE-2023-28103 is a high-severity vulnerability in matrix-org matrix-react-sdk, published on 28 Mar 2023. 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-2023-28103 in the wild and no public exploit code.

Affected packages and fixed versions:
- matrix-react-sdk (npm): affected all versions; fixed in 3.69.0
- matrix-react-sdk (npm): affected all versions; fixed in 3.69.0

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-2023-28103/ (Markdown: https://insights.sbomify.com/CVE-2023-28103/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28103
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28103
- OSV: https://osv.dev/vulnerability/CVE-2023-28103

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28103/
Summaries are generated and may contain mistakes; the official description above is the record.