Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-61876

Severity CVSS v4.0:
CRITICAL
Type:
CWE-79 Cross-Site Scripting (XSS)
Publication date:
12/07/2026
Last modified:
12/07/2026

Description

LuCI versions fail to properly encode DHCPv6 lease hostnames before rendering in status tables, allowing adjacent network attackers to inject HTML markup. Attackers can send a DHCPv6 Client FQDN containing script tags that execute in the administrator's browser when viewing DHCP lease pages.

Impact

Vector 4.0
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H CVSS v4.0 Severity and Metrics:

Base Score: 9.40 CRITICAL
Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): Passsive
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): High
Integrity (SI): High
Availability (SA): High

Base Score 4.0
9.40
Severity 4.0
CRITICAL
Vector 3.x
CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 8.80 HIGH
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): High
Integrity (I): High
Availability (A): High

Base Score 3.x
8.80
Severity 3.x
HIGH

References to Advisories, Solutions, and Tools