CVE-2021-42757
MEDIUMCVSS 6.7/10EPSS 0.48%
Last modified
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/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
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
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-42757?
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.
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.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-42757?
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