What is CVE-2020-15851?

CVE-2020-15851 is a critical-severity vulnerability in Nakivo Backup \& Replication Transporter, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2020-09-24.

How severe is CVE-2020-15851?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Auth bypass in Nakivo Backup \& Replication Transporter

CVE-2020-15851

Lack of access control in Nakivo Backup & Replication Transporter version 9.4.0.r43656 allows remote users to access unencrypted backup repositories and the Nakivo Controller configuration via a network accessible transporter service. It is also possible to create or delete backup repositories.

Vulnerability class: Broken Authentication

Published 2020-09-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.015 (73.9th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 74th percentile — 73.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: 0.000

Affected products

Nakivo Backup \& Replication Transporter — versions 9.4.0.r43656

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

labs.f-secure.com/advisories/nakivo-backup-and-replication-multiple-vulnerabili… (Exploit, Third Party Advisory)
helpcenter.nakivo.com/display/RN/v10.3+Release+Notes (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2020-15851?: CVE-2020-15851 is a critical-severity vulnerability in Nakivo Backup \& Replication Transporter, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2020-09-24.
How severe is CVE-2020-15851?: Critical severity. CVSS v3 base score is 9.8 out of 10.