# CVE-2023-4256: Tcpreplay: tcprewrite: double free in tcpedit_dlt_cleanup() in plugins/dlt_plugins.c

> A local attacker can cause a denial of service in tcpreplay's tcprewrite tool by providing a crafted file that triggers a double free error.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Dec 2023
- **Updated:** 13 Feb 2025
- **Also known as:** DEBIAN-CVE-2023-4256, GHSA-pjxj-fcrm-89x2, UBUNTU-CVE-2023-4256

## What is CVE-2023-4256?

CVE-2023-4256 is a medium-severity use after free vulnerability in Broadcom Tcpreplay, published on 21 Dec 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Within tcpreplay's tcprewrite, a double free vulnerability has been identified in the tcpedit_dlt_cleanup() function within plugins/dlt_plugins.c. This vulnerability can be exploited by supplying a specifically crafted file to the tcprewrite binary. This flaw enables a local attacker to initiate a Denial of Service (DoS) attack.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2023-4256?

It affects 3 products.


Products: Broadcom Tcpreplay, Fedoraproject Extra Packages for Enterprise Linux, Fedoraproject Fedora.

## How do I fix CVE-2023-4256?

Apply the vendor's patch.

## Is CVE-2023-4256 being exploited?

There is no known exploitation of CVE-2023-4256 in the wild and no public exploit code.

## Other vulnerabilities in Broadcom Tcpreplay

- [CVE-2018-18408](https://insights.sbomify.com/CVE-2018-18408/): Use after free in n/a (critical 9.8)
- [CVE-2020-12740](https://insights.sbomify.com/CVE-2020-12740/): Memory corruption in n/a (critical 9.1)
- [CVE-2025-51006](https://insights.sbomify.com/CVE-2025-51006/): Use after free in n/a (high 7.8)
- [CVE-2022-37047](https://insights.sbomify.com/CVE-2022-37047/): Memory corruption in n/a (high 7.8)
- [CVE-2022-37048](https://insights.sbomify.com/CVE-2022-37048/): Memory corruption in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-4256 and fix it if it is affected.

What it is: CVE-2023-4256 is a medium-severity use after free vulnerability in Broadcom Tcpreplay, published on 21 Dec 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-4256 in the wild and no public exploit code.

Affected product: Broadcom Tcpreplay. 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-2023-4256/ (Markdown: https://insights.sbomify.com/CVE-2023-4256/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-4256
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-4256
- OSV: https://osv.dev/vulnerability/CVE-2023-4256

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-4256/
Summaries are generated and may contain mistakes; the official description above is the record.