# CVE-2023-28356: Denial of service in Rocket.Chat

> A maliciously crafted message causes a hot loop in Rocket.Chat, consuming excessive CPU and rendering the service unresponsive.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 May 2023
- **Updated:** 27 Jan 2025
- **Also known as:** GHSA-cw96-grj5-m243

## What is CVE-2023-28356?

CVE-2023-28356 is a high-severity denial of service vulnerability in Rocket.chat Rocket.chat, published on 11 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability has been identified where a maliciously crafted message containing a specific chain of characters can cause the chat to enter a hot loop on one of the processes, consuming ~120% CPU and rendering the service unresponsive.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2023-28356?

It affects 1 product.


Products: Rocket.chat Rocket.chat.

## How do I fix CVE-2023-28356?

No fix has been published for CVE-2023-28356 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-28356 being exploited?

There is no known exploitation of CVE-2023-28356 in the wild and no public exploit code.

## Other vulnerabilities in Rocket.chat Rocket.chat

- [CVE-2026-58066](https://insights.sbomify.com/CVE-2026-58066/): Auth bypass in Rocket.Chat (critical 9.8)
- [CVE-2026-29198](https://insights.sbomify.com/CVE-2026-29198/): SQL injection in Rocket.Chat (critical 9.8)
- [CVE-2023-28316](https://insights.sbomify.com/CVE-2023-28316/): Security feature bypass in Rocket.Chat (critical 9.8)
- [CVE-2022-44567](https://insights.sbomify.com/CVE-2022-44567/): Command injection in Rocket.chat - Electron Desktop (critical 9.8)
- [CVE-2021-22910](https://insights.sbomify.com/CVE-2021-22910/): Code injection in Rocket.Chat server (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-28356 and fix it if it is affected.

What it is: CVE-2023-28356 is a high-severity denial of service vulnerability in Rocket.chat Rocket.chat, published on 11 May 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-2023-28356 in the wild and no public exploit code.

Affected product: Rocket.chat Rocket.chat. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2023-28356/ (Markdown: https://insights.sbomify.com/CVE-2023-28356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-28356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-28356
- OSV: https://osv.dev/vulnerability/CVE-2023-28356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-28356/
Summaries are generated and may contain mistakes; the official description above is the record.