What is CVE-2021-47813?

CVE-2021-47813 is a high-severity vulnerability in Nsauditor Backup Key Recovery, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.5/10. Published 2026-01-16.

How severe is CVE-2021-47813?

High severity. CVSS v3 base score is 7.5 out of 10.

Buffer overflow in Nsauditor Backup Key Recovery

CVE-2021-47813

Backup Key Recovery 2.2.7 contains a denial of service vulnerability that allows attackers to crash the application by overflowing the registration code input field. Attackers can paste a large buffer of 256 repeated characters into the registration key field to trigger application instability and potential crash.

Vulnerability class: Buffer Overflow

Published 2026-01-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (33.2th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: -0.000

Affected products

Nsauditor Backup Key Recovery — versions 2.2.7.0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

www.exploit-db.com/exploits/49966 (exploit)
www.nsauditor.com (product)
www.vulncheck.com/advisories/backup-key-recovery-denial-of-service-poc (third-party-advisory)

Frequently asked questions

What is CVE-2021-47813?: CVE-2021-47813 is a high-severity vulnerability in Nsauditor Backup Key Recovery, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.5/10. Published 2026-01-16.
How severe is CVE-2021-47813?: High severity. CVSS v3 base score is 7.5 out of 10.