# CVE-2026-8356: Stack buffer overflow in PPT presentation import

> A stack buffer overflow in LibreOffice's PPT import allows attackers to execute arbitrary code via a malicious presentation file.

- **Severity:** Medium 5.4 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P`)
- **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:** Yes
- **Published:** 15 Jun 2026
- **Updated:** 15 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-8356, GHSA-8r7p-3qw5-wxm5, UBUNTU-CVE-2026-8356

## What is CVE-2026-8356?

CVE-2026-8356 is a medium-severity memory corruption vulnerability in The Document Foundation LibreOffice, published on 15 Jun 2026. 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

LibreOffice can import presentations in the legacy binary PPT format. A stack buffer overflow existed when importing a colour-replacement record. Two fixed-size colour tables were filled from the file, but the write position was not reset between the two passes over the record, so a file whose combined colour counts exceeded the table size wrote past the end of the tables on the stack. In fixed versions the unused second pass is no longer read into those tables.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2026-8356?


## How do I fix CVE-2026-8356?

Apply the vendor's patch.

## Is CVE-2026-8356 being exploited?

There is no known exploitation of CVE-2026-8356 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8356 and fix it if it is affected.

What it is: CVE-2026-8356 is a medium-severity memory corruption vulnerability in The Document Foundation LibreOffice, published on 15 Jun 2026. 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-2026-8356 in the wild and no public exploit code.

Affected product: The Document Foundation LibreOffice. 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-2026-8356/ (Markdown: https://insights.sbomify.com/CVE-2026-8356/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8356
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8356
- OSV: https://osv.dev/vulnerability/CVE-2026-8356

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8356/
Summaries are generated and may contain mistakes; the official description above is the record.