CVE-2021-40391Public exploitNetwork attack vector

Code execution via unchecked drill tool number

Published Nov 19, 2021 · Updated Aug 4, 2024

Out-of-bounds write in Gerbv 2.7.0 and development builds allows attackers to execute code through a crafted Excellon drill file. drill_parse_T_code reports an out-of-range tool number but continues, then uses the unrestricted value to index and write image->aperture. The attack requires the file to be opened or processed by an exposed conversion service; heap corruption can crash the process or support arbitrary code execution.

CVSS severity10.0
Critical
EPSS probability2.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Gerbv 2.7.0 and development builds allows attackers to execute code through a crafted Excellon drill file. drill_parse_T_code reports an out-of-range tool number but continues, then uses the unrestricted value to index and write image->aperture. The attack requires the file to be opened or processed by an exposed conversion service; heap corruption can crash the process or support arbitrary code execution.

The record

CVE
CVE-2021-40391
Published
Nov 19, 2021
Updated
Aug 4, 2024
Vendor
Gerbv
Product
Gerbv
Classifications
CWE-755, CWE-787, CWE-390, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Gerbv 2.7.0 , Gerbv dev (commit b5f1eacd) ,Gerbv forked dev (commit 71493260)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Gerbv · Gerbvversion=Gerbv 2.7.0 , Gerbv dev (commit b5f1eacd) ,Gerbv forked dev (commit 71493260)

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
10.0Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions
CWE-787Out-of-bounds Write
CWE-390Detection of Error Condition Without Action
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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