CVE & CISA-KEV Catalog

CVE-2021-27861

MEDIUM
4.7
CVSS v3
NVD

Description

Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)

CWE-130CWE-290

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorAdjacent
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged

Impact

ConfidentialityNone
IntegrityLow
AvailabilityNone

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Exploit Intelligence

0.58%probability of exploitation in 30 days
43rdpercentile

Moderate risk: more likely to be exploited than 43% of all known CVEs.

References

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Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.