Security readout for executives and security teams
Plain-English summary
CVE-2021-28200 is a denial-of-service risk in ASUS BMC firmware used to remotely manage servers. A privileged user can enter an oversized value in the CD media configuration page and crash the BMC web service. It matters most where BMC access is broadly reachable or shared across administrators.
Executive priority
Handle as a moderate infrastructure hygiene item. Prioritize faster if affected BMC interfaces are reachable outside a restricted management network, support critical servers, or rely on shared privileged accounts.
Technical view
The issue is a CWE-120 buffer overflow in the ASUS BMC web management CD media configuration function. The CVSS 3.1 score is 4.9: network reachable, low complexity, high privileges required, no user interaction, and availability-only impact. The supplied sources name affected firmware versions but do not name fixed versions.
Likely exposure
Exposure is limited to ASUS systems running the listed BMC firmware versions, including ASMB9-iKVM and multiple RS, ESC, WS, E700, Z11PA, and KNPA models. Risk increases if the BMC web interface is reachable from non-management networks or if privileged accounts are widely shared.
Exploitation context
The bundle does not show CISA KEV listing, public exploitation, or exploit code. The described impact is abnormal termination of the web service after privileged access. Treat it as an authenticated remote availability issue, not evidence of unauthenticated compromise or data theft.
Researcher notes
Evidence is specific about vulnerability type, affected versions, privileges, and availability impact. It is incomplete on fixed versions, practical exploitability, and real-world exploitation. Avoid assuming code execution or confidentiality impact because the supplied CVSS vector and description only support web service disruption.
Mitigation direction
- Check ASUS and TWCERT advisories for fixed BMC firmware or vendor guidance.
- Upgrade affected BMC firmware when ASUS provides an applicable fixed release.
- Restrict BMC web access to dedicated management networks or VPN only.
- Limit privileged BMC accounts and remove unused administrator access.
- Monitor BMC web service crashes and unexpected management-plane outages.
Validation and detection
- Inventory ASUS BMC models and firmware versions across server assets.
- Compare installed firmware against the affected version list in the CVE bundle.
- Confirm BMC web interfaces are not exposed to general corporate or internet networks.
- Review BMC administrator accounts for least-privilege and current ownership.
- Check management logs for web service abnormal terminations or repeated failures.
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-120: 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-2021-28200 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
- Medium
- CVSS
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
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:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H1.23.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.asus.com/content/ASUS-Product-Security-Advisory/CVE reference · x_refsource_MISC
- https://www.asus.com/tw/support/callus/CVE reference · x_refsource_MISC
- https://www.twcert.org.tw/tw/cp-132-4570-4d216-1.htmlCVE 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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.