# CVE-2023-36747: Memory corruption in GTKWave

> A heap-based buffer overflow in GTKWave allows attackers to execute arbitrary code or cause denial of service by tricking a user into opening a malicious .fst file.

- **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/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:** Yes
- **Published:** 8 Jan 2024
- **Updated:** 4 Nov 2025
- **Also known as:** DEBIAN-CVE-2023-36747, GHSA-cf7q-84pj-gw7g, UBUNTU-CVE-2023-36747

## What is CVE-2023-36747?

CVE-2023-36747 is a high-severity memory corruption vulnerability in Tonybybell Gtkwave, published on 8 Jan 2024. 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

Multiple heap-based buffer overflow vulnerabilities exist in the fstReaderIterBlocks2 fstWritex len functionality of GTKWave 3.3.115. A specially crafted .fst file can lead to memory corruption. A victim would need to open a malicious file to trigger these vulnerabilities.This vulnerability concerns the handling of `len` in `fstWritex` when `beg_time` does not match the start of the time table.

Weakness: CWE-787 (Out-of-bounds Write), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2023-36747?

It affects 1 product.


Products: Tonybybell Gtkwave.

## How do I fix CVE-2023-36747?

Apply the vendor's patch.

## Is CVE-2023-36747 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-36747 exists.

## Other vulnerabilities in Tonybybell Gtkwave

- [CVE-2023-34087](https://insights.sbomify.com/CVE-2023-34087/): Memory corruption in GTKWave (high 7.8)
- [CVE-2023-34436](https://insights.sbomify.com/CVE-2023-34436/): Memory corruption in GTKWave (high 7.8)
- [CVE-2023-35004](https://insights.sbomify.com/CVE-2023-35004/): Integer overflow in GTKWave (high 7.8)
- [CVE-2023-35057](https://insights.sbomify.com/CVE-2023-35057/): Integer overflow in GTKWave (high 7.8)
- [CVE-2023-35702](https://insights.sbomify.com/CVE-2023-35702/): Memory corruption in GTKWave (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-36747 and fix it if it is affected.

What it is: CVE-2023-36747 is a high-severity memory corruption vulnerability in Tonybybell Gtkwave, published on 8 Jan 2024. 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-36747 exists.

Affected product: Tonybybell Gtkwave. 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-2023-36747/ (Markdown: https://insights.sbomify.com/CVE-2023-36747/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-36747
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-36747
- OSV: https://osv.dev/vulnerability/CVE-2023-36747

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-36747/
Summaries are generated and may contain mistakes; the official description above is the record.