How severe is CVE-2021-40391?

CVE-2021-40391 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40391?

CVE-2021-40391 primarily affects Gerbv Project Gerbv. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-40391?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-40391 published?

CVE-2021-40391 was published on 2021-11-19 and last updated on 2026-06-17.

CVE-2021-40391

CVE-2021-40391 is a critical-severity vulnerability in Gerbv Project Gerbv with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-755.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-755
Affected product: Gerbv Project Gerbv
Published: 2021-11-19
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-40391?: 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.
How severe is CVE-2021-40391?: CVE-2021-40391 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40391?: CVE-2021-40391 primarily affects Gerbv Project Gerbv. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-40391?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40391 published?: CVE-2021-40391 was published on 2021-11-19 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:gerbv_project:gerbv:2.7.0:-:*:*:*:*:*:*
cpe:2.3:a:gerbv_project:gerbv:2.7.0:dev:*:*:*:*:*:*
cpe:2.3:a:gerbv_project:gerbv:2.7.0:forked_dev:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*

More vulnerabilities in Gerbv Project Gerbv

CVE-2021-40394 — Critical (CVSS 9.8): An out-of-bounds write vulnerability exists in the RS-274X aperture macro variables handling functionality of Gerbv…
CVE-2021-40393 — Critical (CVSS 9.8): An out-of-bounds write vulnerability exists in the RS-274X aperture macro variables handling functionality of Gerbv…
CVE-2021-40401 — High (CVSS 8.6): A use-after-free vulnerability exists in the RS-274X aperture definition tokenization functionality of Gerbv 2.7.0 and…
CVE-2021-40402 — High (CVSS 7.5): An out-of-bounds read vulnerability exists in the RS-274X aperture macro multiple outline primitives functionality of…
CVE-2021-40400 — High (CVSS 7.5): An out-of-bounds read vulnerability exists in the RS-274X aperture macro outline primitive functionality of Gerbv 2.7.0…
CVE-2021-40403 — Medium (CVSS 6.3): An information disclosure vulnerability exists in the pick-and-place rotation parsing functionality of Gerbv 2.7.0 and…

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