Vulnerability in Cisco Catalyst 9800
CVE-2021-34767
A vulnerability in IPv6 traffic processing of Cisco IOS XE Wireless Controller Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a Layer 2 (L2) loop in a configured VLAN, resulting in a denial of service (DoS) condition for that VLAN. The vulnerability is due to a logic error when processing specific link-local IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that would flow inbound through the wired interface of an affected device. A successful exploit could allow the attacker to cause traffic drops in the affected VLAN, thus triggering the DoS condition.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.008 (56.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ewlc-ipv… (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-34767?
- CVE-2021-34767 is a high-severity vulnerability in Cisco Catalyst 9800, classified under Always-Incorrect Control Flow Implementation. CVSS score: 7.4/10. Published 2021-09-23.
- How severe is CVE-2021-34767?
- High severity. CVSS v3 base score is 7.4 out of 10.
- Is CVE-2021-34767 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.