CVE-2026-20084
Cisco Cisco IOS XE Software
At a glance
- Source
- NVD
- EPSS
- EPSS 0.36 % · percentile 30 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- cisco
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
- CWE-400 — Uncontrolled Resource Consumption (DoS)
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H | cisco |
| CVSS 3.1 | HIGH 8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H | NVD · psirt@cisco.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-15431
- GCVE · GCVE-0-2026-20084
CERT-FR advisories
- CERTFR-2026-AVI-0361 — Multiples vulnérabilités dans Cisco IOS et IOS XE · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:cisco:ios_xe:16.6.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.3:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.4:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.4a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.5:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.6:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.7:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.8:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.9:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.6.10:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.7.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.8.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.8.1a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.8.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.3:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.4:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.5:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.6:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.7:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.9.8:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1e:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.10.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1b:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.11.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1c:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.1s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.2:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.2s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.3:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.3a:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.3s:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.4:*:*:*:*:*:*:*cpe:2.3:o:cisco:ios_xe:16.12.4a:*:*:*:*:*:*:*- +67 more
Affected products
| Product | Versions |
|---|---|
| Cisco · Cisco IOS XE Software | affected 16.6.1 ; affected 16.6.2 ; affected 16.6.3 ; affected 16.6.4 ; affected 16.6.5 ; affected 16.6.4a |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |