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CVE Record

CVE-2021-4204: An out-of-bounds (OOB) memory access flaw was found in the Linux kernel's eBPF due to an Improper Input Val...

An out-of-bounds (OOB) memory access flaw was found in the Linux kernel's eBPF due to an Improper Input Validation. This flaw allows a local attacker with a special privilege to crash the system or leak internal information.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-4204 is a Linux kernel eBPF memory access flaw. A local attacker with special privilege could crash the system or leak internal information. This is mainly a server and appliance hardening issue, not a remotely reachable internet bug based on the provided sources.

Executive priority

Treat this as a moderate-priority kernel maintenance issue. It can affect system availability and confidentiality, but the provided evidence points to local privileged access rather than remote compromise or known exploitation.

Technical view

The CVE describes out-of-bounds memory access in Linux kernel eBPF caused by improper input validation. The provided affected range says Linux kernel v5.8 or later. Reported impacts are denial of service and possible information disclosure by a local privileged attacker.

Likely exposure

Exposure is likely on Linux systems running kernel v5.8 or later, including distributions or appliances that incorporated affected kernels. Systems with users, services, containers, or administrators able to exercise eBPF-related privileges deserve priority review.

Exploitation context

The source bundle does not cite active exploitation, and the CVE is not listed as KEV. The attack context is local and requires special privilege. Evidence is insufficient to claim public weaponization or remote exploitability.

Researcher notes

Focus on kernel version lineage, distribution backports, and privilege boundaries around eBPF use. The bundle lacks CVSS, exact fixed versions, and exploit evidence, so validation should be vendor-specific rather than based only on upstream version numbers.

Mitigation direction

  • Check Linux distribution and appliance vendor advisories for fixed kernel packages.
  • Apply vendor-provided kernel updates after compatibility testing.
  • Prioritize multi-user servers, container hosts, and shared administrative systems.
  • Reduce unnecessary local accounts and privileged service access pending vendor guidance.

Validation and detection

  • Inventory Linux hosts and appliances running kernel v5.8 or later.
  • Map each affected asset to Red Hat, Debian, NetApp, or relevant vendor status.
  • Confirm whether local users or services have eBPF-related special privileges.
  • Verify patched systems are running vendor-confirmed fixed kernel builds.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2021-4204 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/akernelAffects Linux kernel v5.8 or laterListed
Weakness

CWE details

CWE-20

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.