Resource exhaustion in Cisco iOS Xe Software
CVE-2026-20084
A vulnerability in the DHCP snooping feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause BOOTP packets to be forwarded between VLANs, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of BOOTP packets on Cisco Catalyst 9000 Series Switches. An attacker could exploit this vulnerability by sending BOOTP request packets to an affected device. A successful exploit could allow an attacker to forward BOOTP packets from one VLAN to another, resulting in BOOTP VLAN leakage and potentially leading to high CPU utilization. This makes the device unreachable (either through console or remote management) and unable to forward traffic, resulting in a DoS condition. Note: This vulnerability can be exploited with either unicast or broadcast BOOTP packets. There are workarounds that address this vulnerability.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (26.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Cisco iOS Xe Software — versions 16.6.1, 16.6.2, 16.6.3
- Cisco iOS Xe — versions 16.10.1, 16.10.1e, 16.10.1s
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-20084?
- CVE-2026-20084 is a high-severity vulnerability in Cisco iOS Xe Software, classified under Uncontrolled Resource Consumption. CVSS score: 8.6/10. Published 2026-03-25.
- How severe is CVE-2026-20084?
- High severity. CVSS v3 base score is 8.6 out of 10.