CVE-2021-27861: ieee 802.2
CVSS: 4.7v3.1MediumModified
Published 27-09-2022Last modified 04-11-2025
Vulnerability summary
CVE-2021-27861 is a medium (CVSS 4.7) vulnerability in ieee 802.2. EPSS estimates a 0.66% chance of exploitation in the next 30 days, higher than 50.7% of scored vulnerabilities.
CVSS score
4.7/10
010
Medium · v3.1 (CVE.org)EPSS score
0.66%
0%100%
Low · +0.05 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 27-09-2022PublishedVulnerability first disclosed.
- 04-11-2025Last modifiedVulnerability information updated.
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)
CVSS metrics
2 scores · 2 sources · 1 versionMedium 4.7Preferred score · CVE.org (CNA)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:NSourcesAll 2 agree
- NVDNIST4.7MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
EPSS trend
Probability
0.66%
Chance of exploitation in the next 30 days
Percentile
51%
Versus all other CVEs
30-day change
+0.05 pp
From 0.62% on 19-09-2026
19-09-202619-10-2026
EPSS score0.66%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-130Improper Handling of Length Parameter InconsistencyThe product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.
- CWE-290Authentication Bypass by SpoofingThis attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
Affected systems
Ieee2 products
- 802.2802.2h-1997
- ieee_802.2≤ 802.2h-1997
Ietf2 products
- draft-ietf-v6ops-ra-guard08
- p802.1qD1.0 | ≤ d1.0
2 vendors · 4 products
References
6 links- datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Third Party Advisory
- standards.ieee.org/ieee/802.2/1048/Third Party Advisory
- standards.ieee.org/ieee/802.1Q/10323/Third Party Advisory