PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal_CVE-2026-0300

{
    "lastseen": "",
    "description": "A buffer overflow vulnerability in the User-ID\u2122 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. \n\nThe risk of this issue is greatly reduced if you secure access to the User-ID\u2122 Authentication Portal per the  best practice guidelines https://knowledgebase.paloaltonetworks.com/KCSArticleDetail  by restricting access to only trusted internal IP addresses.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.",
    "published": "2026-05-06T18:57:39.876Z",
    "modified": "2026-05-06T19:24:13.881Z",
    "type": "cve",
    "title": "PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID\u2122 Authentication Portal",
    "source": "palo_alto",
    "references": "https://security.paloaltonetworks.com/CVE-2026-0300",
    "id": "CVE-2026-0300",
    "bulletinFamily": "",
    "cwe": [
        "CWE-787"
    ],
    "cvelist": null,
    "sourceData": "Palo Alto Networks PAN-OS 12.1.0\nPalo Alto Networks PAN-OS 11.2.0\nPalo Alto Networks PAN-OS 11.1.0\nPalo Alto Networks PAN-OS 10.2.0",
    "sourceHref": "",
    "cvss": {
        "score": 9.3,
        "severity": "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "PAN-OS",
    "version": "All",
    "vendor": "Palo Alto Networks",
    "ai_description": "Unauthenticated buffer overflow vulnerability in User-ID Authentication Portal",
    "ai_severity": "Critical",
    "ai_vendor": "Palo Alto Networks",
    "ai_product": "PAN-OS",
    "ai_version": "10.2.0, 11.1.0, 11.2.0, 12.1.0",
    "ai_score": 9.3
}