CVE-2021-42757

Name: CVE-2021-42757
Creator: NVD / NIST
Published: 2021-12-08T11:15:11.84+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.7/10EPSS 0.48%

Last modified Jun 17, 2026

CVE-2021-42757 is a medium-severity vulnerability rated 6.7/10 on the CVSS scale. A buffer overflow [CWE-121] in the TFTP client library of FortiOS before 6.4.7 and FortiOS 7.0.0 through 7.0.2, may allow an authenticated local attacker to achieve arbitrary code execution via specially crafted command line arguments.. EPSS estimates a 0.48% chance of exploitation in the next 30 days.

Description

A buffer overflow [CWE-121] in the TFTP client library of FortiOS before 6.4.7 and FortiOS 7.0.0 through 7.0.2, may allow an authenticated local attacker to achieve arbitrary code execution via specially crafted command line arguments.

Metrics

CVSS 3.1

6.7/10

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.48%

37.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Fortinet	Fortiadc	>= 5.0.0, <= 6.1.5
Fortinet	Fortiadc	>= 6.2.0, <= 6.2.2
Fortinet	Fortianalyzer	>= 6.0.0, <= 6.4.7
Fortinet	Fortianalyzer	>= 7.0.0, <= 7.0.2
Fortinet	Fortimail	>= 5.4.0, <= 6.2.7
Fortinet	Fortimail	>= 6.4.0, <= 6.4.6
Fortinet	Fortimail	>= 7.0.0, <= 7.0.2
Fortinet	Fortimanager	>= 6.0.0, <= 6.4.7
Fortinet	Fortimanager	>= 7.0.0, <= 7.0.2
Fortinet	Fortindr	>= 1.1.0, <= 1.5.2
Fortinet	Fortios-6k7k	<= 6.2.8
Fortinet	Fortios-6k7k	6.4.2
Fortinet	Fortios-6k7k	6.4.6
Fortinet	Fortiportal	>= 5.0.0, <= 6.0.10
Fortinet	Fortiproxy	>= 1.0.0, <= 2.0.7
Fortinet	Fortiproxy	7.0.0
Fortinet	Fortiproxy	7.0.1
Fortinet	Fortivoice	>= 6.0.0, <= 6.0.10
Fortinet	Fortivoice	>= 6.4.0, <= 6.4.4
Fortinet	Fortiweb	>= 5.0.0, <= 6.3.16
Fortinet	Fortiweb	6.4.0
Fortinet	Fortiweb	6.4.1
Fortinet	Fortios	>= 5.0.0, <= 6.0.13
Fortinet	Fortios	>= 6.2.0, <= 6.2.9
Fortinet	Fortios	>= 6.4.0, <= 6.4.7
Fortinet	Fortios	>= 7.0.0, <= 7.0.2
Fortinet	Fortirecorder Firmware	>= 2.6.0, <= 6.0.10
Fortinet	Fortirecorder Firmware	>= 6.4.0, <= 6.4.2
Fortinet	Fortiswitch	>= 6.0.0, <= 6.4.9
Fortinet	Fortiswitch	>= 7.0.0, <= 7.0.3

References

https://fortiguard.com/advisory/FG-IR-21-173Vendor Advisory
https://fortiguard.com/advisory/FG-IR-21-173Vendor Advisory

Timeline

Published: Dec 8, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-42757?

How severe is CVE-2021-42757?

CVE-2021-42757 has a CVSS score of 6.7/10 (MEDIUM severity). The EPSS model estimates a 0.48% probability of exploitation in the next 30 days.

How do I fix CVE-2021-42757?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-42757?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST