CVE-2026-20084

highpriority · track · 0EPSS 0.004 · 30 %ileDEEUNLRUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.36% (30th) EPSS
CVSS 8.6 · high
Is it mine?
459 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

8.6
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.6highAV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4
v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · NCSC-NL NL
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USCWE-400US
05

affected products (459)

Products and version ranges known to be affected.

showing 20 of 459
06

advisories (3)

Vendor and ecosystem advisories describing this.

  • NCSC-2026-0104Kwetsbaarheden verholpen in Cisco IOS XE SoftwareNL2026-03-26csaf · ncsc_nlNL

    Cisco heeft kwetsbaarheden verholpen in Cisco IOS XE Software, specifiek voor verschillende producten zoals Catalyst 9000 Series Switches, Catalyst CW9800 Family, en Cisco Meraki.

  • WID-SEC-W-2026-0874Cisco IOS und IOS XE Software: Mehrere SchwachstellenDeutsch2026-03-25csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Cisco IOS XE, Cisco IOS und Cisco Catalyst ausnutzen, um sich erweiterte Rechte zu verschaffen, beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Cross-Site-Scripting-Angriffe durchzuführen, Daten zu manipulieren, vertrauliche Informationen offenzulegen und einen Denial-of-Service-Zustand herbeizuführen.

  • cisco-sa-bootp-WuBhNBxACisco IOS XE Software for Catalyst 9000 Series Switches DHCP Snooping Denial of Service Vulnerability2026-03-25csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75297"].

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafncsc_nlcert_bundNVDCVE.orgMITRE
published 2026-03-25modified 2026-06-17
09

references (3)

External citations — patches, advisories, analysis.

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