CVE-2021-43041 json
An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5.
published 2021-12-06 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29995
- cvss
- 8.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.4%
- EPSS 2.4% chance of exploitation in 30 days, percentile 83%
- public exploits
- 0
- none known
Summary
An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. A crafted HTTP request could induce a format string vulnerability in the privileged vaultServer application.
Patch / fix
- kaseya unitrends_backup 10.5.5
Exploit prediction
2.36% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- cyberonesecurity.com https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1 referenced PoC, tagged "exploit" by a source, unverified
- cyberonesecurity.com https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
Classification
- Weakness
-
- CWE-134 Use of Externally-Controlled Format String
References
-
cyberonesecurity.com
/blog/exploiting-kaseya-unitrends-backup-appliance-part-1
exploit, third-party-advisory
-
cyberonesecurity.com
/blog/exploiting-kaseya-unitrends-backup-appliance-part-2
exploit, third-party-advisory
-
helpdesk.kaseya.com
/hc/en-gb/articles/4412762258961
vendor-advisory
Sources
- CVE List CVE-2021-43041
- NVD CVE-2021-43041
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.