# CVE-2018-20452: Use after free in n/a

> Attackers can cause a crash or potentially execute code via a crafted file due to invalid memory management in libxls.

- **Severity:** High 8.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Dec 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-20452, GHSA-3hq6-4m9g-pfg4, UBUNTU-CVE-2018-20452

## What is CVE-2018-20452?

CVE-2018-20452 is a high-severity use after free vulnerability in n/a, published on 25 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

The read_MSAT_body function in ole.c in libxls 1.4.0 has an invalid free that allows attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted file, because of inconsistent memory management (new versus free) in ole2_read_header in ole.c.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2018-20452?

It affects 1 product.


Products: Libxls Project Libxls.

## How do I fix CVE-2018-20452?

Upgrade to a fixed version.

## Is CVE-2018-20452 being exploited?

There is no known exploitation of CVE-2018-20452 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2017-2910](https://insights.sbomify.com/CVE-2017-2910/): Memory corruption in libxls (high 8.8)
- [CVE-2017-12108](https://insights.sbomify.com/CVE-2017-12108/): Integer overflow in libxls (high 8.8)
- [CVE-2017-12109](https://insights.sbomify.com/CVE-2017-12109/): Integer overflow in libxls (high 8.8)
- [CVE-2017-12110](https://insights.sbomify.com/CVE-2017-12110/): Integer overflow in libxls (high 8.8)
- [CVE-2017-12111](https://insights.sbomify.com/CVE-2017-12111/): Memory corruption in libxls (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-20452 and fix it if it is affected.

What it is: CVE-2018-20452 is a high-severity use after free vulnerability in n/a, published on 25 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-2018-20452 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-2018-20452/ (Markdown: https://insights.sbomify.com/CVE-2018-20452/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-20452
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-20452
- OSV: https://osv.dev/vulnerability/CVE-2018-20452

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-20452/
Summaries are generated and may contain mistakes; the official description above is the record.