# CVE-2019-19334: Memory corruption in libyang

> A stack-based buffer overflow in libyang allows attackers to cause denial of service or execute code via malicious YANG files.

- **Severity:** High 8.1 (`CVSS:3.0/AV:N/AC:H/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:** 6 Dec 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-19334, GHSA-936c-h6q8-79c4

## What is CVE-2019-19334?

CVE-2019-19334 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 6 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In all versions of libyang before 1.0-r5, a stack-based buffer overflow was discovered in the way libyang parses YANG files with a leaf of type "identityref". An application that uses libyang to parse untrusted YANG files may be vulnerable to this flaw, which would allow an attacker to cause a denial of service or possibly gain code execution.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2019-19334?

It affects 3 products.


Products: Cesnet Libyang, Fedoraproject Fedora, Redhat Enterprise Linux.

## How do I fix CVE-2019-19334?

Upgrade to a fixed version.

## Is CVE-2019-19334 being exploited?

There is no known exploitation of CVE-2019-19334 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2019-20393](https://insights.sbomify.com/CVE-2019-20393/): Memory corruption in n/a (high 8.8)
- [CVE-2019-20394](https://insights.sbomify.com/CVE-2019-20394/): Use after free in n/a (high 8.8)
- [CVE-2019-20397](https://insights.sbomify.com/CVE-2019-20397/): Memory corruption in n/a (high 8.8)
- [CVE-2019-19333](https://insights.sbomify.com/CVE-2019-19333/): Memory corruption in libyang (high 8.1)
- [CVE-2023-26917](https://insights.sbomify.com/CVE-2023-26917/): Null dereference in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-19334 and fix it if it is affected.

What it is: CVE-2019-19334 is a high-severity memory corruption vulnerability in Fedoraproject Fedora, published on 6 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-2019-19334 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2019-19334/ (Markdown: https://insights.sbomify.com/CVE-2019-19334/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-19334
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-19334
- OSV: https://osv.dev/vulnerability/CVE-2019-19334

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-19334/
Summaries are generated and may contain mistakes; the official description above is the record.