# CVE-2019-9717: Denial of service in n/a

> Attackers can cause denial of service via CPU exhaustion using crafted Matroska files in Libav's subtitle decoder.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Sep 2019
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-g8wg-jvvh-f2j6, UBUNTU-CVE-2019-9717

## What is CVE-2019-9717?

CVE-2019-9717 is a medium-severity denial of service vulnerability in Libav Libav, published on 19 Sep 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

In Libav 12.3, a denial of service in the subtitle decoder allows attackers to hog the CPU via a crafted video file in Matroska format, because srt_to_ass in libavcodec/srtdec.c has a complex format argument to sscanf.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2019-9717?

It affects 1 product.


Products: Libav Libav.

## How do I fix CVE-2019-9717?

No fix has been published for CVE-2019-9717 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-9717 being exploited?

There is no known exploitation of CVE-2019-9717 in the wild and no public exploit code.

## Other vulnerabilities in Libav Libav

- [CVE-2014-3984](https://insights.sbomify.com/CVE-2014-3984/): Multiple unspecified vulnerabilities in Libav before 0.8.12 allow remote attackers to have unknown impact and vectors. (critical 10.0)
- [CVE-2017-9051](https://insights.sbomify.com/CVE-2017-9051/): Null dereference in n/a (critical 9.8)
- [CVE-2014-4609](https://insights.sbomify.com/CVE-2014-4609/): Integer overflow in n/a (high 8.8)
- [CVE-2019-9719](https://insights.sbomify.com/CVE-2019-9719/): Memory corruption in n/a (high 8.8)
- [CVE-2018-5766](https://insights.sbomify.com/CVE-2018-5766/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-9717 and fix it if it is affected.

What it is: CVE-2019-9717 is a medium-severity denial of service vulnerability in Libav Libav, published on 19 Sep 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2019-9717 in the wild and no public exploit code.

Affected product: Libav Libav. 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-2019-9717/ (Markdown: https://insights.sbomify.com/CVE-2019-9717/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-9717
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-9717
- OSV: https://osv.dev/vulnerability/CVE-2019-9717

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-9717/
Summaries are generated and may contain mistakes; the official description above is the record.