CVE-2021-43041

HIGHNVD 8.88.8—

8.8

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.

CVSS v3: 8.8
EG Score: 8.8(medium)
EPSS: 80.9%
KEV: Not listed

Published

December 6, 2021

Last Modified

November 21, 2024

References (6)

cve@mitrehttps://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961
cve@mitrehttps://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1
cve@mitrehttps://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2
af854a3a-2127-422b-91ae-364da2661108https://helpdesk.kaseya.com/hc/en-gb/articles/4412762258961
af854a3a-2127-422b-91ae-364da2661108https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-1
af854a3a-2127-422b-91ae-364da2661108https://www.cyberonesecurity.com/blog/exploiting-kaseya-unitrends-backup-appliance-part-2

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-134Use of Externally-Controlled Format String

Data Freshness Timeline

(refreshed 11× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 06:54 UTCEG score recompute
2026-05-26 06:54 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-43041?

CVE-2021-43041 is a high vulnerability published on December 6, 2021. 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.

When was CVE-2021-43041 disclosed?

CVE-2021-43041 was first published in the National Vulnerability Database on December 6, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-43041 actively exploited?

CVE-2021-43041 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 80.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-43041?

CVE-2021-43041 has a CVSS v3 base score of 8.8 (NVD).

How do I remediate CVE-2021-43041?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-43041, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-43041

📅 Published

🔄 Last Modified

🔗 References (6)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-43041?

🔗 Related CVEs(same CWE)

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Published

Last Modified

References (6)

Frequently asked(5)

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