# CVE-2023-4491: Easy Address Book Web Server Buffer overflow vulnerability

> An attacker can achieve arbitrary code execution by sending a long username string to the search endpoint of the Easy Address Book Web Server.

- **Severity:** Critical 9.8 (`CVSS:3.1/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:** 4 Oct 2023
- **Updated:** 5 Sep 2024
- **Also known as:** GHSA-5wvp-xjf2-pj96

## What is CVE-2023-4491?

CVE-2023-4491 is a critical memory corruption vulnerability in EFS Software Easy Address Book Web Server, published on 4 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Buffer overflow vulnerability in Easy Address Book Web Server 1.6 version. The exploitation of this vulnerability could allow an attacker to send a very long username string to /searchbook.ghp, asking for the name via a POST request, resulting in arbitrary code execution on the remote machine.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2023-4491?

It affects 1 product.


Products: Easy Address Book Web Server Project Easy Address Book Web Server.

## How do I fix CVE-2023-4491?

No fix has been published for CVE-2023-4491 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-4491 being exploited?

There is no known exploitation of CVE-2023-4491 in the wild and no public exploit code.

## Other vulnerabilities in EFS Software Easy Address Book Web Server

- [CVE-2023-4492](https://insights.sbomify.com/CVE-2023-4492/): Easy Address Book Web Server XSS vulnerability (medium 6.1)
- [CVE-2023-4493](https://insights.sbomify.com/CVE-2023-4493/): Easy Address Book Web Server Stored XSS vulnerability (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-4491 and fix it if it is affected.

What it is: CVE-2023-4491 is a critical memory corruption vulnerability in EFS Software Easy Address Book Web Server, published on 4 Oct 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-2023-4491 in the wild and no public exploit code.

Affected product: EFS Software Easy Address Book Web Server. 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-2023-4491/ (Markdown: https://insights.sbomify.com/CVE-2023-4491/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4491
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4491
- OSV: https://osv.dev/vulnerability/CVE-2023-4491

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4491/
Summaries are generated and may contain mistakes; the official description above is the record.