# CVE-2026-8358: Heap buffer overflow in spreadsheet tracked-changes import

> Heap buffer overflow in LibreOffice Calc allows attackers to execute arbitrary code or cause denial of service via a crafted spreadsheet with duplicate change identifiers.

- **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:** 16 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-8358, GHSA-gpc5-jgqj-xp2q, UBUNTU-CVE-2026-8358

## What is CVE-2026-8358?

CVE-2026-8358 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 Calc can import tracked changes from a spreadsheet document. A heap buffer overflow existed when a document reused the same change identifier for two different kinds of change. The importer then treated one change object as a different, larger type and wrote past the end of its allocation. In fixed versions records with a duplicate identifier are rejected.

Weakness: CWE-843 (Access of Resource Using Incompatible Type), CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-8358?


## How do I fix CVE-2026-8358?

Apply the vendor's patch.

## Is CVE-2026-8358 being exploited?

There is no known exploitation of CVE-2026-8358 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8358 and fix it if it is affected.

What it is: CVE-2026-8358 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-2026-8358 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-2026-8358/ (Markdown: https://insights.sbomify.com/CVE-2026-8358/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8358
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8358
- OSV: https://osv.dev/vulnerability/CVE-2026-8358

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-8358/
Summaries are generated and may contain mistakes; the official description above is the record.