# CVE-2019-11873: wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity size is greater than a client identity size.


- **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
- **Fix available:** Yes
- **Published:** 23 May 2019
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-11873, GHSA-6rpx-83hc-92h9, UBUNTU-CVE-2019-11873

## What is CVE-2019-11873?

CVE-2019-11873 is a critical vulnerability in Wolfssl Wolfssl, published on 23 May 2019. 

### Official description

wolfSSL 4.0.0 has a Buffer Overflow in DoPreSharedKeys in tls13.c when a current identity size is greater than a client identity size. An attacker sends a crafted hello client packet over the network to a TLSv1.3 wolfSSL server. The length fields of the packet: record length, client hello length, total extensions length, PSK extension length, total identity length, and identity length contain their maximum value which is 2^16. The identity data field of the PSK extension of the packet contains the attack data, to be stored in the undefined memory (RAM) of the server. The size of the data is about 65 kB. Possibly the attacker can perform a remote code execution attack.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2019-11873?

It affects 1 product.


Products: Wolfssl Wolfssl.

## How do I fix CVE-2019-11873?

Upgrade to a fixed version.

## Is CVE-2019-11873 being exploited?

There is no known exploitation of CVE-2019-11873 in the wild and no public exploit code.

## Other vulnerabilities in Wolfssl Wolfssl

- [CVE-2024-5991](https://insights.sbomify.com/CVE-2024-5991/): Buffer overread in domain name matching (critical 10.0)
- [CVE-2021-37155](https://insights.sbomify.com/CVE-2021-37155/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-36177](https://insights.sbomify.com/CVE-2020-36177/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2896](https://insights.sbomify.com/CVE-2014-2896/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2897](https://insights.sbomify.com/CVE-2014-2897/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-11873 and fix it if it is affected.

What it is: CVE-2019-11873 is a critical vulnerability in Wolfssl Wolfssl, published on 23 May 2019. 
Exploitation: There is no known exploitation of CVE-2019-11873 in the wild and no public exploit code.

Affected product: Wolfssl Wolfssl. 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-2019-11873/ (Markdown: https://insights.sbomify.com/CVE-2019-11873/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-11873
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-11873
- OSV: https://osv.dev/vulnerability/CVE-2019-11873

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-11873/
Summaries are generated and may contain mistakes; the official description above is the record.