CVE-2021-42755: Integer overflow in dhcpd daemon

Published Jul 5, 2022
·
Updated

An integer overflow / wraparound vulnerability [CWE-190] in FortiSwitch 7.0.2 and below, 6.4.9 and below, 6.2.x, 6.0.x; FortiRecorder 6.4.2 and below, 6.0.10 and below; FortiOS 7.0.2 and below, 6.4.8 and below, 6.2.10 and below, 6.0.x; FortiProxy 7.0.0, 2.0.6 and below, 1.2.x, 1.1.x, 1.0.x; FortiVoiceEnterprise 6.4.3 and below, 6.0.10 and below dhcpd daemon may allow an unauthenticated and network adjacent attacker to crash the dhcpd deamon, resulting in potential denial of service.

Other sources

An integer overflow / wraparound vulnerability [CWE-190] in the FortiOS, FortiProxy, FortiSwitch, FortiRecoder, and FortiVoiceEnterprisedhcpd daemon may allow an unauthenticated and network adjacent attacker to crash the dhcpd deamon, resulting in potential denial of service.

FortiGuard

Affected Software

171 affected components
Fortinet FortiProxy>=1.0.0<=1.0.7
Fortinet FortiProxy>=1.1.0<=1.1.6
Fortinet FortiProxy>=1.2.0<=1.2.13
Fortinet FortiProxy>=2.0.0<=2.0.6
Fortinet FortiProxy=7.0.0
Fortinet FortiVoice=5.3.0
Fortinet FortiVoice=5.3.1
Fortinet FortiVoice=5.3.2
Fortinet FortiVoice=5.3.3
Fortinet FortiVoice=5.3.4
Fortinet FortiVoice=5.3.5
Fortinet FortiVoice=5.3.6
Fortinet FortiVoice=5.3.7
Fortinet FortiVoice=5.3.8
Fortinet FortiVoice=5.3.10
Fortinet FortiVoice=5.3.11
Fortinet FortiVoice=5.3.12
Fortinet FortiVoice=5.3.13
Fortinet FortiVoice=5.3.14
Fortinet FortiVoice=5.3.15
Fortinet FortiVoice=5.3.16
Fortinet FortiVoice=5.3.17
Fortinet FortiVoice=5.3.18
Fortinet FortiVoice=5.3.19
Fortinet FortiVoice=5.3.20
Fortinet FortiVoice=5.3.21
Fortinet FortiVoice=5.3.22
Fortinet FortiVoice=5.3.23
Fortinet FortiVoice=5.3.24
Fortinet FortiVoice=5.3.25
Fortinet FortiVoice=5.3.26
Fortinet FortiVoice=6.0.0
Fortinet FortiVoice=6.0.1
Fortinet FortiVoice=6.0.2
Fortinet FortiVoice=6.0.3
Fortinet FortiVoice=6.0.4
Fortinet FortiVoice=6.0.5
Fortinet FortiVoice=6.0.6
Fortinet FortiVoice=6.0.7
Fortinet FortiVoice=6.0.8
Fortinet FortiVoice=6.0.9
Fortinet FortiVoice=6.0.10
Fortinet FortiVoice=6.4.0
Fortinet FortiVoice=6.4.1
Fortinet FortiVoice=6.4.2
Fortinet FortiVoice=6.4.3
Fortinet FortiOS=5.4.0
Fortinet FortiOS=5.4.1
Fortinet FortiOS=5.4.2
Fortinet FortiOS=5.4.3
Fortinet FortiOS=5.4.4
Fortinet FortiOS=5.4.5
Fortinet FortiOS=5.4.6
Fortinet FortiOS=5.4.7
Fortinet FortiOS=5.4.8
Fortinet FortiOS=5.4.9
Fortinet FortiOS=5.4.10
Fortinet FortiOS=5.4.11
Fortinet FortiOS=5.4.12
Fortinet FortiOS=5.4.13
Fortinet FortiOS=5.6.0
Fortinet FortiOS=5.6.1
Fortinet FortiOS=5.6.2
Fortinet FortiOS=5.6.3
Fortinet FortiOS=5.6.4
Fortinet FortiOS=5.6.5
Fortinet FortiOS=5.6.6
Fortinet FortiOS=5.6.7
Fortinet FortiOS=5.6.8
Fortinet FortiOS=5.6.9
Fortinet FortiOS=5.6.10
Fortinet FortiOS=5.6.11
Fortinet FortiOS=5.6.12
Fortinet FortiOS=5.6.13
Fortinet FortiOS=5.6.14
Fortinet FortiOS=6.0.0
Fortinet FortiOS=6.0.1
Fortinet FortiOS=6.0.2
Fortinet FortiOS=6.0.3
Fortinet FortiOS=6.0.4
Fortinet FortiOS=6.0.5
Fortinet FortiOS=6.0.6
Fortinet FortiOS=6.0.7
Fortinet FortiOS=6.0.8
Fortinet FortiOS=6.0.9
Fortinet FortiOS=6.0.10
Fortinet FortiOS=6.0.11
Fortinet FortiOS=6.0.12
Fortinet FortiOS=6.0.13
Fortinet FortiOS=6.0.14
Fortinet FortiOS=6.2.0
Fortinet FortiOS=6.2.1
Fortinet FortiOS=6.2.2
Fortinet FortiOS=6.2.3
Fortinet FortiOS=6.2.4
Fortinet FortiOS=6.2.5
Fortinet FortiOS=6.2.6
Fortinet FortiOS=6.2.7
Fortinet FortiOS=6.2.8
Fortinet FortiOS=6.2.9
Fortinet FortiOS=6.2.10
Fortinet FortiOS=6.4.0
Fortinet FortiOS=6.4.1
Fortinet FortiOS=6.4.2
Fortinet FortiOS=6.4.3
Fortinet FortiOS=6.4.4
Fortinet FortiOS=6.4.5
Fortinet FortiOS=6.4.6
Fortinet FortiOS=6.4.7
Fortinet FortiOS=7.0.0
Fortinet FortiOS=7.0.1
Fortinet FortiOS=7.0.2
Fortinet Fortirecorder Firmware=6.0.0
Fortinet Fortirecorder Firmware=6.0.1
Fortinet Fortirecorder Firmware=6.0.2
Fortinet Fortirecorder Firmware=6.0.3
Fortinet Fortirecorder Firmware=6.0.4
Fortinet Fortirecorder Firmware=6.0.5
Fortinet Fortirecorder Firmware=6.0.6
Fortinet Fortirecorder Firmware=6.0.7
Fortinet Fortirecorder Firmware=6.0.8
Fortinet Fortirecorder Firmware=6.0.9
Fortinet Fortirecorder Firmware=6.0.10
Fortinet Fortirecorder Firmware=6.4.0
Fortinet Fortirecorder Firmware=6.4.1
Fortinet Fortirecorder Firmware=6.4.2
Fortinet FortiSwitch>=6.0.0<=6.0.7
Fortinet FortiSwitch>=6.2.0<=6.2.7
Fortinet FortiSwitch>=6.4.0<=6.4.9
Fortinet FortiSwitch>=7.0.0<=7.0.2
Fortinet FortiVoice=5.3.0
Fortinet FortiVoice=5.3.1
Fortinet FortiVoice=5.3.2
Fortinet FortiVoice=5.3.3
Fortinet FortiVoice=5.3.4
Fortinet FortiVoice=5.3.5
Fortinet FortiVoice=5.3.6
Fortinet FortiVoice=5.3.7
Fortinet FortiVoice=5.3.8
Fortinet FortiVoice=5.3.10
Fortinet FortiVoice=5.3.11
Fortinet FortiVoice=5.3.12
Fortinet FortiVoice=5.3.13
Fortinet FortiVoice=5.3.14
Fortinet FortiVoice=5.3.15
Fortinet FortiVoice=5.3.16
Fortinet FortiVoice=5.3.17
Fortinet FortiVoice=5.3.18
Fortinet FortiVoice=5.3.19
Fortinet FortiVoice=5.3.20
Fortinet FortiVoice=5.3.21
Fortinet FortiVoice=5.3.22
Fortinet FortiVoice=5.3.23
Fortinet FortiVoice=5.3.24
Fortinet FortiVoice=5.3.25
Fortinet FortiVoice=5.3.26
Fortinet FortiVoice=6.0.0
Fortinet FortiVoice=6.0.1
Fortinet FortiVoice=6.0.2
Fortinet FortiVoice=6.0.3
Fortinet FortiVoice=6.0.4
Fortinet FortiVoice=6.0.5
Fortinet FortiVoice=6.0.6
Fortinet FortiVoice=6.0.7
Fortinet FortiVoice=6.0.8
Fortinet FortiVoice=6.0.9
Fortinet FortiVoice=6.0.10
Fortinet FortiVoice=6.4.0
Fortinet FortiVoice=6.4.1
Fortinet FortiVoice=6.4.2
Fortinet FortiVoice=6.4.3

Event History

Jul 5, 2022
Advisory Published
via FortiGuard·12:00 AM
Data Sourced
via FortiGuard·12:00 AM
DescriptionSeverityWeaknessAffected Software
Jul 18, 2022
CVE Published
via MITRE·04:35 PM
Data Sourced
via MITRE·04:35 PM
DescriptionSeverityWeakness
Oct 25, 2024
Advisory Published
via FortiGuard·12:00 AM
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2021-42755?

CVE-2021-42755 has been classified with a severity level of high due to the potential for remote code execution resulting from the integer overflow vulnerability.

2

How do I fix CVE-2021-42755?

To resolve CVE-2021-42755, it is recommended to upgrade your FortiSwitch, FortiRecorder, or FortiOS to the latest versions provided by Fortinet.

3

What systems are affected by CVE-2021-42755?

CVE-2021-42755 affects FortiSwitch versions 7.0.2 and below, FortiRecorder versions 6.4.2 and below, and multiple versions of FortiOS and FortiProxy.

4

Can CVE-2021-42755 be exploited remotely?

Yes, CVE-2021-42755 can be exploited remotely, allowing attackers to potentially execute arbitrary code on the affected devices.

5

What precautions should I take regarding CVE-2021-42755?

In addition to applying security updates, consider monitoring network traffic for unusual activities and ensuring proper firewall rules are in place to mitigate risks.

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203