CVE-2021-43040
HIGHCVSS 8.8/10EPSS 1.77%
Last modified
CVE-2021-43040 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The privileged vaultServer could be leveraged to create arbitrary writable files, leading to privilege escalation.. EPSS estimates a 1.77% chance of exploitation in the next 30 days.
Description
An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The privileged vaultServer could be leveraged to create arbitrary writable files, leading to privilege escalation.
Metrics
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Kaseya | Unitrends Backup | >= 10.0, < 10.5.5 |
References
- https://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961Vendor Advisory
- https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1Exploit, Third Party Advisory
- https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2Exploit, Third Party Advisory
- https://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961Vendor Advisory
- https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1Exploit, Third Party Advisory
- https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2Exploit, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-43040?
An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. The privileged vaultServer could be leveraged to create arbitrary writable files, leading to privilege escalation.
How severe is CVE-2021-43040?
CVE-2021-43040 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.77% probability of exploitation in the next 30 days.
How do I fix CVE-2021-43040?
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-2021-43040?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST