# CVE-2026-102566: CTranslate2 before 4.8.1 Heap Buffer Overflow via model.bin

> Attackers can achieve arbitrary code execution or cause crashes by providing malicious model files to the CTranslate2 library.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **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:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-7xqx-34h9-2w97

## What is CVE-2026-102566?

CVE-2026-102566 is a high-severity memory corruption vulnerability in OpenNMT CTranslate2, published on 29 Sep 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

CTranslate2 before 4.8.1 contains a heap-based buffer overflow in the binary model loader that fails to validate payload length against allocated buffer size. Attackers can craft malicious model files with oversized payload lengths to write past heap allocation boundaries, causing crashes or arbitrary code execution.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-102566?


## How do I fix CVE-2026-102566?

No fix has been published for CVE-2026-102566 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-102566 being exploited?

There is no known exploitation of CVE-2026-102566 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102566 and fix it if it is affected.

What it is: CVE-2026-102566 is a high-severity memory corruption vulnerability in OpenNMT CTranslate2, published on 29 Sep 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-2026-102566 in the wild and no public exploit code.

Affected product: OpenNMT CTranslate2. 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-2026-102566/ (Markdown: https://insights.sbomify.com/CVE-2026-102566/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102566
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102566
- OSV: https://osv.dev/vulnerability/CVE-2026-102566

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102566/
Summaries are generated and may contain mistakes; the official description above is the record.