CVE-2021-21557
No known exploitation. EPSS puts it in the 25th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
Dell PowerEdge Server BIOS and select Dell Precision Rack BIOS contain an out-of-bounds array access vulnerability. A local malicious user with high privileges may potentially exploit this vulnerability, leading to a denial of service, arbitrary code execution, or information disclosure in System Management Mode.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.3% chance of exploitation activity in the next 30 days, which ranks it in the 25th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
5 events over 1256 days, from the signal feeds we watch.
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
- poweredge r640 firmwareHardware Firmware / bios-uefi
- poweredge r740 firmwareHardware Firmware / bios-uefi
- poweredge r740xd firmwareHardware Firmware / bios-uefi
- poweredge r940 firmwareHardware Firmware / bios-uefi
- poweredge r540 firmwareHardware Firmware / printer-peripheral
- poweredge r440 firmwareHardware Firmware / printer-peripheral
- poweredge t440 firmwareHardware Firmware / storage-nas
- poweredge xr2 firmwareHardware Firmware / storage-nas
And 24 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L
Scored 8.1 by NVD.
How it is reached
- Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required HighRequires admin or elevated privileges
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability LowReduced performance or intermittent disruption of service
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- CollectionT1005Data from Local Systemmedium confidence
- Initial AccessT1190Exploit Public-Facing Applicationlow confidence
Sources
References in the record
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