# CVE-2018-19837: Denial of service in n/a

> Attackers can cause denial of service via stack consumption by submitting a crafted Sass file to applications using LibSass.

- **Severity:** Medium 6.5 (`CVSS:3.0/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:** Yes
- **Published:** 4 Dec 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-19837, GHSA-c774-r78g-7qj4, UBUNTU-CVE-2018-19837

## What is CVE-2018-19837?

CVE-2018-19837 is a medium-severity denial of service vulnerability in n/a, published on 4 Dec 2018. 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 LibSass prior to 3.5.5, Sass::Eval::operator()(Sass::Binary_Expression*) inside eval.cpp allows attackers to cause a denial-of-service resulting from stack consumption via a crafted sass file, because of certain incorrect parsing of '%' as a modulo operator in parser.cpp.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-19837?

It affects 1 product.


Products: Sass-Lang Libsass.

## How do I fix CVE-2018-19837?

Upgrade to a fixed version.

## Is CVE-2018-19837 being exploited?

There is no known exploitation of CVE-2018-19837 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-11499](https://insights.sbomify.com/CVE-2018-11499/): Use after free in n/a (critical 9.8)
- [CVE-2022-26592](https://insights.sbomify.com/CVE-2022-26592/): Memory corruption in n/a (high 8.8)
- [CVE-2018-19827](https://insights.sbomify.com/CVE-2018-19827/): Use after free in n/a (high 8.8)
- [CVE-2018-11694](https://insights.sbomify.com/CVE-2018-11694/): Null dereference in n/a (high 8.8)
- [CVE-2018-11695](https://insights.sbomify.com/CVE-2018-11695/): Null dereference in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-19837 and fix it if it is affected.

What it is: CVE-2018-19837 is a medium-severity denial of service vulnerability in n/a, published on 4 Dec 2018. 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-2018-19837 in the wild and no public exploit code.

Affected product: n/a. 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-2018-19837/ (Markdown: https://insights.sbomify.com/CVE-2018-19837/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-19837
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-19837
- OSV: https://osv.dev/vulnerability/CVE-2018-19837

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-19837/
Summaries are generated and may contain mistakes; the official description above is the record.