# CVE-2023-35784: Use after free in n/a

> A double free or use-after-free in LibreSSL's SSL_clear function allows attackers to execute arbitrary code or cause denial of service.

- **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:** Yes
- **Published:** 16 Jun 2023
- **Updated:** 17 Dec 2024
- **Also known as:** BELL-CVE-2023-35784, GHSA-w423-44w8-64mh

## What is CVE-2023-35784?

CVE-2023-35784 is a critical use after free vulnerability in Openbsd Openbsd, published on 16 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A double free or use after free could occur after SSL_clear in OpenBSD 7.2 before errata 026 and 7.3 before errata 004, and in LibreSSL before 3.6.3 and 3.7.x before 3.7.3. NOTE: OpenSSL is not affected.

Weakness: CWE-416 (Use After Free), CWE-415 (Double Free)

## Which versions are affected by CVE-2023-35784?

It affects 2 products.


Products: Openbsd Libressl, Openbsd Openbsd.

## How do I fix CVE-2023-35784?

Upgrade to a fixed version.

## Is CVE-2023-35784 being exploited?

There is no known exploitation of CVE-2023-35784 in the wild and no public exploit code.

## Other vulnerabilities in Openbsd Openbsd

- [CVE-2021-46880](https://insights.sbomify.com/CVE-2021-46880/): Auth bypass in n/a (critical 9.8)
- [CVE-2015-5334](https://insights.sbomify.com/CVE-2015-5334/): Memory corruption in LibreSSL (critical 9.8)
- [CVE-2015-5333](https://insights.sbomify.com/CVE-2015-5333/): Denial of service in LibreSSL (high 7.5)
- [CVE-2014-9424](https://insights.sbomify.com/CVE-2014-9424/): Use after free in n/a (high 7.5)
- [CVE-2018-8970](https://insights.sbomify.com/CVE-2018-8970/): Security feature bypass in n/a (high 7.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-35784 and fix it if it is affected.

What it is: CVE-2023-35784 is a critical use after free vulnerability in Openbsd Openbsd, published on 16 Jun 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-2023-35784 in the wild and no public exploit code.

Affected product: Openbsd Openbsd. 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-2023-35784/ (Markdown: https://insights.sbomify.com/CVE-2023-35784/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-35784
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-35784
- OSV: https://osv.dev/vulnerability/CVE-2023-35784

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-35784/
Summaries are generated and may contain mistakes; the official description above is the record.