# CVE-2021-40391

## Summary

- **CVE ID:** CVE-2021-40391
- **Severity:** CRITICAL
- **CVSS Score:** 10 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)
- **CWE:** CWE-390
- **Published:** Nov 19, 2021
- **Last Modified:** Mar 13, 2026

## Description

An out-of-bounds write vulnerability exists in the drill format T-code tool number functionality of Gerbv 2.7.0, dev (commit b5f1eacd), and the forked version of Gerbv (commit 71493260). A specially-crafted drill file can lead to code execution. An attacker can provide a malicious file to trigger this vulnerability.

## Affected Products

- n/a — Gerbv (Gerbv 2.7.0 , Gerbv dev (commit b5f1eacd) ,Gerbv forked dev (commit 71493260))

## References

- [CNA](https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1402)
- [CNA](https://lists.debian.org/debian-lts-announce/2021/12/msg00003.html)
- [CNA](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUM5GIUZJ7AVHVCXDZW6ZVCAPV2ISN47/)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.47%
- **EPSS Percentile:** 64.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._