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CVE-2021-28809

Missing Authentication for Critical Function in RTRR Server in HBS3

Critical9.8EPSS 16.1%
Published
Updated
Reserved
Assigned by
qnap

Description

An improper access control vulnerability has been reported to affect certain legacy versions of HBS 3. If exploited, this vulnerability allows attackers to compromise the security of the operating system.QNAP have already fixed this vulnerability in the following versions of HBS 3: QTS 4.3.6: HBS 3 v3.0.210507 and later QTS 4.3.4: HBS 3 v3.0.210506 and later QTS 4.3.3: HBS 3 v3.0.210506 and later

Scores

CVSS scores of CVE-2021-28809, by who scored it
Scored byCVSSScoreVector
qnapCNA (assigner)3.1Critical9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Modified3.1Critical9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
16.1% · top 3.1% of all CVEs (6 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.

Weakness

Affected products

What to do

Solution: QNAP have already fixed this vulnerability in the following versions of HBS 3: QTS 4.3.6: HBS 3 v3.0.210507 and later QTS 4.3.4: HBS 3 v3.0.210506 and later QTS 4.3.3: HBS 3 v3.0.210506 and later

References (2)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .