CVE-2021-27861
MEDIUMCVSS 4.7/10EPSS 0.58%
Last modified
CVE-2021-27861 is a medium-severity vulnerability rated 4.7/10 on the CVSS scale. Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers). EPSS estimates a 0.58% chance of exploitation in the next 30 days.
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)
Metrics
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Ieee | Ieee 802.2 | <= 802.2h-1997 |
| Ietf | P802.1q | <= d1.0 |
References
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Third Party Advisory
- https://standards.ieee.org/ieee/802.1Q/10323/Third Party Advisory
- https://standards.ieee.org/ieee/802.2/1048/Third Party Advisory
- https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/Third Party Advisory
- https://standards.ieee.org/ieee/802.1Q/10323/Third Party Advisory
- https://standards.ieee.org/ieee/802.2/1048/Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-27861?
Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using LLC/SNAP headers with invalid length (and optionally VLAN0 headers)
How severe is CVE-2021-27861?
CVE-2021-27861 has a CVSS score of 4.7/10 (MEDIUM severity). The EPSS model estimates a 0.58% probability of exploitation in the next 30 days.
How do I fix CVE-2021-27861?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
Are you affected by CVE-2021-27861?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST