CVE-2026-0300

CRITICAL KEV

Palo Alto PAN-OS User-ID Authentication Portal - Unauthenticated Root RCE

Title source: manual
STIX 2.1

Exploitation Summary

CVE-2026-0300 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added May 6, 2026. EIP tracks 13 public exploits from researchers including adminlove520, qassam-315, p3Nt3st3r-sTAr.

AI-analyzed exploit summary The repository contains a functional Python-based PoC for CVE-2026-0300, a critical buffer overflow vulnerability in PAN-OS User-ID Portal. The exploit demonstrates an out-of-bounds write leading to potential RCE via a crafted POST request.

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. 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. Prisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.

Exploits (13)

github WORKING POC 4 stars
by adminlove520 · pythonpoc
https://github.com/adminlove520/CVE-Poc_All_in_One/tree/main/2026/CVE-2026-0300

The repository contains a functional Python-based PoC for CVE-2026-0300, a critical buffer overflow vulnerability in PAN-OS User-ID Portal. The exploit demonstrates an out-of-bounds write leading to potential RCE via a crafted POST request.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Palo Alto Networks PAN-OS (12.1, 11.2, 11.1, 10.2)
No auth needed
Prerequisites: Network access to target · User-ID Portal service running on port 6082
devstral-2 · analyzed May 26, 2026 Full analysis →
nomisec WORKING POC 2 stars
by qassam-315 · poc
https://github.com/qassam-315/PAN-OS-User-ID-Buffer-Overflow-PoC

This repository contains a functional Python-based proof-of-concept exploit for CVE-2026-0300, a buffer overflow vulnerability in Palo Alto Networks PAN-OS User-ID Authentication Portal. The exploit demonstrates remote code execution by sending a crafted POST request to overflow a fixed-size buffer, potentially allowing control over the instruction pointer.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Palo Alto Networks PAN-OS 12.1, 11.2, 11.1, 10.2
No auth needed
Prerequisites: Network access to the target PAN-OS User-ID Portal (default port 6082) · Python 3.9 or higher
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec WORKING POC 1 stars
by p3Nt3st3r-sTAr · poc
https://github.com/p3Nt3st3r-sTAr/CVE-2026-0300-POC

This repository contains a functional Python-based exploit for CVE-2026-0300, a critical buffer overflow vulnerability in Palo Alto Networks PAN-OS User-ID™ Authentication Portal. The exploit leverages a crafted POST request to trigger an out-of-bounds write, leading to remote code execution via a reverse shell payload.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Palo Alto Networks PAN-OS 12.1, 11.2, 11.1, 10.2
No auth needed
Prerequisites: Python 3.9+ · network access to target · listener setup for reverse shell
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec WORKING POC 1 stars
by mr-r3b00t · poc
https://github.com/mr-r3b00t/CVE-2026-0300

This repository contains a functional honeypot for CVE-2026-0300, designed to emulate the PAN-OS User-ID Authentication Portal vulnerability. The honeypot script (`pan_userid_honeypot.py`) is deployed via an installer script that sets up a Python-based service to monitor and log exploitation attempts on ports 6080/6081/6082.

Classification
Working Poc 95%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: PAN-OS User-ID Authentication Portal
No auth needed
Prerequisites: Ubuntu Server (22.04/24.04 LTS) · Python 3 · CAP_NET_BIND_SERVICE capability
devstral-2 · analyzed May 07, 2026 Full analysis →
github SCANNER
by ridhinva · pythonpoc
https://github.com/ridhinva/CVE-2026-0300-PANOS-RCE

The repository contains a Python script that scans for potentially vulnerable Palo Alto Networks PAN-OS endpoints associated with CVE-2026-0300, a buffer overflow vulnerability in the User-ID Authentication Portal (Captive Portal) service. It checks for accessible endpoints but does not include exploit code for achieving RCE.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Theoretical
Target: Palo Alto Networks PAN-OS (PA-Series and VM-Series firewalls)
No auth needed
Prerequisites: network access to target endpoints
devstral-2 · analyzed May 23, 2026 Full analysis →
github WORKING POC
by lu4m575 · pythonpoc
https://github.com/lu4m575/CVE-2026-0300

This repository contains a functional exploit for CVE-2026-0300, targeting a memory corruption vulnerability in a PHP-based application. The exploit constructs a malicious HTTP POST request with a buffer overflow payload to achieve remote code execution via a reverse shell.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Unknown PHP-based application (likely a web service listening on port 6082)
No auth needed
Prerequisites: Target IP and port · Attacker-controlled listener IP and port · Network connectivity to the target
devstral-2 · analyzed May 22, 2026 Full analysis →
github WORKING POC
by XZ1r0 · pythonpoc
https://github.com/XZ1r0/cve-2026-poc-collection/tree/main/other/CVE-2026-0300-POC

This repository contains a functional exploit for CVE-2026-0300, a buffer overflow vulnerability in PAN-OS User-ID Portal leading to remote code execution. The PoC constructs a malicious POST request with a reverse shell payload and sends it to the target.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Palo Alto Networks PAN-OS 12.1, 11.2, 11.1, 10.2
No auth needed
Prerequisites: Python 3.9+ · network access to target · listener setup for reverse shell
devstral-2 · analyzed May 21, 2026 Full analysis →
github SUSPICIOUS
by ByteWraith1 · poc
https://github.com/ByteWraith1/CVE-2026-0300

The repository claims to be a PoC for CVE-2026-0300 but lacks actual exploit code, instead redirecting users to an external link (tinyurl.com). The README is vague and lacks technical details about the vulnerability.

Classification
Suspicious 90%
Attack Type
Other
Complexity
Theoretical
Reliability
Theoretical
Target: Palo Alto Networks PAN-OS
No auth needed
Prerequisites: Python 3.8+ · requests library · argparse library
devstral-2 · analyzed May 17, 2026 Full analysis →
nomisec SCANNER
by shizuku198411 · poc
https://github.com/shizuku198411/CVE-2026-0300

This repository contains a non-destructive exposure survey tool for CVE-2026-0300, which is a buffer overflow vulnerability in Palo Alto Networks PAN-OS User-ID Authentication Portal. The tool checks for network and HTTP(S) reachability, portal-related paths, and basic response fingerprints to assess exposure without exploiting the vulnerability.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Palo Alto Networks PAN-OS User-ID Authentication Portal
No auth needed
Prerequisites: Network access to the target PAN-OS device · User-ID Authentication Portal enabled and reachable
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec WORKING POC
by bannned-bit · poc
https://github.com/bannned-bit/CVE-2026-0300-PANOS

The repository contains a functional Python-based proof-of-concept exploit for CVE-2026-0300, targeting an unauthenticated remote code execution vulnerability in Palo Alto Networks PAN-OS User-ID Portal. The exploit crafts a malicious HTTP POST request with a buffer overflow payload to achieve RCE.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Palo Alto Networks PAN-OS User-ID Portal (versions 8.0.x through 10.0.x)
No auth needed
Prerequisites: Python 3.8+ · network access to target · vulnerable PAN-OS version
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec SCANNER
by TailwindRG · poc
https://github.com/TailwindRG/cve-2026-0300-audit

This repository provides read-only audit tooling for CVE-2026-0300, an unauthenticated buffer overflow in the PAN-OS User-ID Authentication Portal. The scripts query the PAN-OS XML API to detect configurations vulnerable to the CVE but do not exploit it.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: PAN-OS (PA-Series and VM-Series firewalls)
Auth required
Prerequisites: PAN-OS API key with read access · Python 3.10 or newer
devstral-2 · analyzed May 07, 2026 Full analysis →
nomisec SCANNER
by 0xBlackash · poc
https://github.com/0xBlackash/CVE-2026-0300

The repository contains a Python script that scans for exposed Palo Alto PAN-OS Captive Portal endpoints vulnerable to CVE-2026-0300, a critical buffer overflow vulnerability. It checks multiple paths and reports if any are accessible, but does not include exploit code.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Palo Alto PAN-OS (User-ID Authentication Portal)
No auth needed
Prerequisites: User-ID Authentication Portal must be enabled and reachable
devstral-2 · analyzed May 07, 2026 Full analysis →

References (3)

Core 3

Scores

CVSS v3 9.8
EPSS 0.3176
EPSS Percentile 98.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation active
Automatable yes
Technical Impact total

Details

CISA KEV 2026-05-06
VulnCheck KEV 2026-05-05
ENISA EUVD EUVD-2026-27879
CWE
CWE-787
Status published
Products (20)
Palo Alto Networks/Cloud NGFW All
Palo Alto Networks/PAN-OS 10.2.0 - 10.2.18-h6
Palo Alto Networks/PAN-OS 11.1.0 - 11.1.15
Palo Alto Networks/PAN-OS 11.2.0 - 11.2.12
Palo Alto Networks/PAN-OS 12.1.0 - 12.1.7
Palo Alto Networks/Prisma Access All
paloaltonetworks/pan-os 10.2.0
paloaltonetworks/pan-os 10.2.1
paloaltonetworks/pan-os 10.2.2
paloaltonetworks/pan-os 10.2.3
... and 10 more
Published May 06, 2026
KEV Added May 06, 2026
Tracked Since May 07, 2026