# CVE-2017-12109: Integer overflow in libxls

> An integer overflow in libxls allows remote code execution via a specially crafted XLS file.

- **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:** 24 Apr 2018
- **Updated:** 16 Sep 2024
- **Also known as:** DEBIAN-CVE-2017-12109, GHSA-9qvr-p35q-rv6h, UBUNTU-CVE-2017-12109

## What is CVE-2017-12109?

CVE-2017-12109 is a high-severity vulnerability in libxls, published on 24 Apr 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

An exploitable integer overflow vulnerability exists in the xls_preparseWorkSheet function of libxls 1.4 when handling a MULRK record. A specially crafted XLS file can cause a memory corruption resulting in remote code execution. An attacker can send malicious XLS file to trigger this vulnerability.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2017-12109?

It affects 1 product.


Products: Libxls Project Libxls.

## How do I fix CVE-2017-12109?

Upgrade to a fixed version.

## Is CVE-2017-12109 being exploited?

There is no known exploitation of CVE-2017-12109 in the wild and no public exploit code.

## Other vulnerabilities in libxls

- [CVE-2017-2910](https://insights.sbomify.com/CVE-2017-2910/): Memory corruption in libxls (high 8.8)
- [CVE-2018-20452](https://insights.sbomify.com/CVE-2018-20452/): Use after free in n/a (high 8.8)
- [CVE-2017-12108](https://insights.sbomify.com/CVE-2017-12108/): 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-2017-12109 and fix it if it is affected.

What it is: CVE-2017-12109 is a high-severity vulnerability in libxls, published on 24 Apr 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-2017-12109 in the wild and no public exploit code.

Affected product: libxls. 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-2017-12109/ (Markdown: https://insights.sbomify.com/CVE-2017-12109/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12109
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12109
- OSV: https://osv.dev/vulnerability/CVE-2017-12109

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-12109/
Summaries are generated and may contain mistakes; the official description above is the record.