HOMEVULNERABILITIESCVE-2021-40391
CRITICAL

CVE-2021-40391

CWE-390Published: November 19, 2021· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-40391 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

Debian1 product(s)
debian linux
Fedora1 product(s)
fedora
gerbv_project1 product(s)
gerbv
Source: NVD CPE · 3 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/12/msg00003.html
ADVISORYhttps://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1402
ADVISORYhttps://lists.debian.org/debian-lts-announce/2021/12/msg00003.html
ADVISORYhttps://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1402

All References (6)

→
https://lists.debian.org/debian-lts-announce/2021/12/msg00003.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUM5GIUZJ7AVHVCXDZW6ZVCAPV2ISN47/
→
https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1402Exploit · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2021/12/msg00003.htmlMailing List · Third Party Advisory
→
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUM5GIUZJ7AVHVCXDZW6ZVCAPV2ISN47/
→
https://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1402Exploit · Third Party Advisory

Quick Facts

CVE IDCVE-2021-40391
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-390
CISA KEVNo
Affected3 vendor(s)
PublishedNov 19, 2021

Related CVEs (CWE-390)

CVE-2026-53434
9.1
CVE-2019-5051
8.8
CVE-2024-49841
7.8
CVE-2025-46367
7.8
CVE-2024-27919
7.5
CVE-2024-30255
7.5

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-40391 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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