Security readout for executives and security teams
Plain-English summary
CVE-2021-28801 is a low-severity information disclosure flaw in QNAP QSS on specific QNAP switch models. A successful attacker could read limited sensitive information from the system. The public data indicates exploitation requires adjacent network access and high attack complexity.
Executive priority
Treat this as routine maintenance unless affected QNAP switches are present in sensitive network segments. The impact is limited information disclosure, and the available evidence does not indicate active exploitation.
Technical view
The issue is an out-of-bounds read in QNAP QSS, classified as CWE-125. It affects QSS versions before 1.0.2 build 20210122 on QSW-M2108-2C, QSW-M2108-2S, and QSW-M2108R-2C. CVSS 3.1 is 3.1 with adjacent attack vector, high complexity, no privileges, no user interaction, and low confidentiality impact.
Likely exposure
Exposure is limited to organizations using the named QNAP switch models with QSS earlier than 1.0.2 build 20210122. The CVSS vector indicates the attacker must be adjacent to the target network, reducing broad internet-scale risk.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. Publicly provided details state potential sensitive information disclosure, but do not provide exploit maturity, observed attacks, or technical attack path details.
Researcher notes
Evidence is limited to the CVE record and QNAP advisory reference. The affected model and fixed-build information is clear, but the source bundle does not include root-cause details, proof-of-concept status, indicators of compromise, or exploitation telemetry.
Mitigation direction
- Upgrade affected switches to QSS 1.0.2 build 20210122 or later.
- Prioritize QSW-M2108-2C, QSW-M2108-2S, and QSW-M2108R-2C devices.
- Review QNAP advisory QSA-21-23 for vendor-specific update guidance.
- Verify switch management access is limited according to normal network administration policy.
Validation and detection
- Inventory QNAP switch models deployed in the environment.
- Check each device's QSS version and build number.
- Confirm affected models are running 1.0.2 build 20210122 or later.
- Document any older QSS installations for update planning.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-28801 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Low
- CVSS
- 3.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N1.61.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.1LowVector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.qnap.com/zh-tw/security-advisory/qsa-21-23CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.