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CVE-2026-0300

Severity CVSS v4.0:
CRITICAL
Type:
CWE-787 Out-of-bounds Write
Publication date:
06/05/2026
Last modified:
12/05/2026

Description

A buffer overflow vulnerability in the User-ID™ Authentication Portal (aka Captive Portal) service of Palo Alto Networks PAN-OS software allows an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets. <br /> <br /> The risk of this issue is greatly reduced if you secure access to the User-ID™ Authentication Portal per the best practice guidelines https://knowledgebase.paloaltonetworks.com/KCSArticleDetail by restricting access to only trusted internal IP addresses.<br /> <br /> Prisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/E:A/AU:Y/R:U/V:C/RE:M/U:Red CVSS v4.0 Severity and Metrics:

Base Score: 9.30 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/E:A/AU:Y/R:U/V:C/RE:M/U:Red

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): High
Confidentiality (SC): Low
Integrity (SI): Low
Availability (SA): None
Automatable (AU): Yes
Recovery (R): User
Value Density (V): Concentrated
Vulnerability Response Effort (RE): Moderate
Provider Urgency (U): Red
Exploit Maturity (E): Attacked

Base Score 4.0
9.30
Severity 4.0
CRITICAL
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS v3.1 Severity and Metrics:

Base Score: 9.80 CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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

Base Score 3.x
9.80
Severity 3.x
CRITICAL

Vulnerable products and versions

CPE From Up to
cpe:2.3:o:paloaltonetworks:pan-os:10.2.0:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.1:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.2:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.3:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.4:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.5:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.6:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:-:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h1:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h12:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h16:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h19:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h21:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h24:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h3:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools