# CVE-2023-4540: DoS in lua-http library

> A crafted request triggers an infinite loop in the lua-http library, causing excessive allocation and denial of service.

- **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:** Yes
- **Published:** 5 Sep 2023
- **Updated:** 4 Apr 2025
- **Also known as:** DEBIAN-CVE-2023-4540, GHSA-947g-gmvh-r5rp, UBUNTU-CVE-2023-4540

## What is CVE-2023-4540?

CVE-2023-4540 is a high-severity denial of service vulnerability in Daurnimator lua-http, published on 5 Sep 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Handling of Exceptional Conditions vulnerability in Daurnimator lua-http library allows Excessive Allocation and a denial of service (DoS) attack to be executed by sending a properly crafted request to the server. 
Such a request causes the program to enter an infinite loop. 

This issue affects lua-http: all versions before commit ddab283.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2023-4540?

It affects 1 product.


Products: Daurnimator Lua-Http.

## How do I fix CVE-2023-4540?

Apply the vendor's patch.

## Is CVE-2023-4540 being exploited?

There is no known exploitation of CVE-2023-4540 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-4540 and fix it if it is affected.

What it is: CVE-2023-4540 is a high-severity denial of service vulnerability in Daurnimator lua-http, published on 5 Sep 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-2023-4540 in the wild and no public exploit code.

Affected product: Daurnimator lua-http. 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-2023-4540/ (Markdown: https://insights.sbomify.com/CVE-2023-4540/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4540
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4540
- OSV: https://osv.dev/vulnerability/CVE-2023-4540

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4540/
Summaries are generated and may contain mistakes; the official description above is the record.