# CVE-2016-4296: Memory corruption in Hancom Office

> A heap buffer overflow in Hancom Office allows remote attackers to execute arbitrary code via a crafted Hcell document.

- **Severity:** High 7.8 (`CVSS:3.0/AV:L/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:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 Jan 2017
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-27v3-wp78-r8ww

## What is CVE-2016-4296?

CVE-2016-4296 is a high-severity memory corruption vulnerability in Hancom Office, published on 6 Jan 2017. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

When opening a Hangul Hcell Document (.cell) and processing a record that uses the CSSValFormat object, Hancom Office 2014 will search for an underscore ("_") character at the end of the string and write a null terminator after it. If the character is at the very end of the string, the application will mistakenly write the null-byte outside the bounds of its destination. This can result in heap corruption that can lead code execution under the context of the application

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

## Which versions are affected by CVE-2016-4296?

It affects 1 product.


Products: Hancom Hancom Office 2014.

## How do I fix CVE-2016-4296?

No fix has been published for CVE-2016-4296 yet. Limit exposure of the affected software until one is available.

## Is CVE-2016-4296 being exploited?

There is no known exploitation of CVE-2016-4296 in the wild and no public exploit code.

## Other vulnerabilities in Hancom Office

- [CVE-2016-4293](https://insights.sbomify.com/CVE-2016-4293/): Memory corruption in n/a (high 7.8)
- [CVE-2016-4290](https://insights.sbomify.com/CVE-2016-4290/): Integer overflow in Hancom Office (high 7.8)
- [CVE-2016-4291](https://insights.sbomify.com/CVE-2016-4291/): Integer overflow in Hancom Office (high 7.8)
- [CVE-2016-4292](https://insights.sbomify.com/CVE-2016-4292/): Memory corruption in Hancom Office (high 7.8)
- [CVE-2016-4294](https://insights.sbomify.com/CVE-2016-4294/): Memory corruption in Hancom Office (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-4296 and fix it if it is affected.

What it is: CVE-2016-4296 is a high-severity memory corruption vulnerability in Hancom Office, published on 6 Jan 2017. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2016-4296 in the wild and no public exploit code.

Affected product: Hancom Office. 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-2016-4296/ (Markdown: https://insights.sbomify.com/CVE-2016-4296/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-4296
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-4296
- OSV: https://osv.dev/vulnerability/CVE-2016-4296

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-4296/
Summaries are generated and may contain mistakes; the official description above is the record.