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CVE-2021-21556

No known exploitation. EPSS puts it in the 21st percentile. A vendor fix is available.

CVSS 3.16.1MediumEPSS percentile21st0.3% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD

NVD CVE.org

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 R640, R740, R740XD, R840, R940, R940xa, MX740c, MX840c, and T640 Server BIOS contain a stack-based buffer overflow vulnerability in systems with NVDIMM-N installed. 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 UEFI or BIOS Preboot Environment.

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.

EPSS21st
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 21st 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.

  1. Patch availablerecord updated
  2. Publishedweakness classified, att&ck mapped

Affected products

And 2 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L

Scored 6.1 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 RequiredA user must click a link, open a file, or perform some action

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

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.

Sources

References in the record

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We'll flag the next CVE, public exploit or patch for Poweredge R640 Firmware, not every advisory.

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