Is CVE-2021-28799 actively exploited?

Yes. CVE-2021-28799 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-28799 be exploited remotely?

The attack vector of CVE-2021-28799 has not been classified yet.

What is the CVSS score of CVE-2021-28799?

CVE-2021-28799 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-28799

HIGHCISA KEVIN THE WILD

CVE-2021-28799

Published: March 31, 2022

EPSS:91.15%probability of exploitation in 30 daysPercentile:99.6th

Official Description

QNAP NAS running HBS 3 contains an improper authorization vulnerability which can allow remote attackers to log in to a device.

NVD Source

CISA KEV Advisory

QNAP NAS Improper Authorization Vulnerability

QNAP NAS running HBS 3 contains an improper authorization vulnerability which can allow remote attackers to log in to a device.

Added to KEV: 2022-03-31Federal patch deadline: 2022-04-21⚠ USED IN RANSOMWARE CAMPAIGNS

Required Action (CISA)

Apply updates per vendor instructions.

Risk Analysis

This improper authorization vulnerability in QNAP NAS running HBS 3 allows remote attackers to log in to a device without proper authentication. The high EPSS score of 0.91146 indicates a very high likelihood of exploitation, making this a critical vulnerability. Its presence in CISA's KEV catalog confirms it has been actively exploited.

This vulnerability is actively exploited in the wild. It is remotely exploitable, allowing attackers to gain unauthorized access to the device.

Recommended Action

Apply the latest security patches and firmware updates for QNAP NAS devices running HBS 3. Ensure strong, unique passwords are used for all accounts and enable multi-factor authentication where possible.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2021-28799 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-28799 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.