# CVE-2019-5096: Use after free in EmbedThis

> Unauthenticated attackers can achieve remote code execution via a use-after-free vulnerability in the GoAhead web server's handling of multi-part/form-data requests.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 3 Dec 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-xcxv-6fr5-34fm

## What is CVE-2019-5096?

CVE-2019-5096 is a critical use after free vulnerability in EmbedThis, published on 3 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An exploitable code execution vulnerability exists in the processing of multi-part/form-data requests within the base GoAhead web server application in versions v5.0.1, v.4.1.1 and v3.6.5. A specially crafted HTTP request can lead to a use-after-free condition during the processing of this request that can be used to corrupt heap structures that could lead to full code execution. The request can be unauthenticated in the form of GET or POST requests, and does not require the requested resource to exist on the server.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2019-5096?

It affects 1 product.


Products: Embedthis Goahead.

## How do I fix CVE-2019-5096?

No fix has been published for CVE-2019-5096 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-5096 being exploited?

There is no known exploitation of CVE-2019-5096 in the wild and no public exploit code.

Public exploit code:

- CVE-2019-5096(UAF in upload handler) exploit cause Denial of Service (github_poc): https://github.com/ianxtianxt/CVE-2019-5096-GoAhead-Web-Server-Dos-Exploit

## Other vulnerabilities in EmbedThis

- [CVE-2017-17562](https://insights.sbomify.com/CVE-2017-17562/): Embedthis GoAhead Remote Code Execution (high 8.1, exploited in the wild)
- [CVE-2021-41615](https://insights.sbomify.com/CVE-2021-41615/): Weak cryptography in n/a (critical 9.8)
- [CVE-2021-43298](https://insights.sbomify.com/CVE-2021-43298/): Security feature bypass in goahead (critical 9.8)
- [CVE-2021-42342](https://insights.sbomify.com/CVE-2021-42342/): File upload in n/a (critical 9.8)
- [CVE-2017-1000471](https://insights.sbomify.com/CVE-2017-1000471/): Null dereference in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-5096 and fix it if it is affected.

What it is: CVE-2019-5096 is a critical use after free vulnerability in EmbedThis, published on 3 Dec 2019. 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-2019-5096 in the wild and no public exploit code.

Affected product: EmbedThis. 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-2019-5096/ (Markdown: https://insights.sbomify.com/CVE-2019-5096/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-5096
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-5096
- OSV: https://osv.dev/vulnerability/CVE-2019-5096

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-5096/
Summaries are generated and may contain mistakes; the official description above is the record.