{"id":"CVE-2026-0300","aliases":["EUVD-2026-27879","GHSA-3vfh-3cpw-2378"],"status":"published","title":"PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal","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. \n\nThe 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.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.","severity":{"version":"4.0","score":9.3,"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","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.41714,"percentile":0.98698,"model":"v2026.06.15"},"facts":{"in_kev":true,"known_exploited":true,"public_exploit":true,"fix_available":false},"cwes":["CWE-787"],"published":"2026-05-06T18:57:39Z","modified":"2026-10-26T19:10:00Z","kev":{"date_added":"2026-05-06","due_date":"2026-05-09","required_action":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented:  - Restrict User-ID Authentication Portal access to only trusted zones.  - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.","known_ransomware_use":"Unknown"},"exploitation":[{"source":"euvd","since":"2026-05-06"},{"source":"kev","since":"2026-05-06"}],"exploits":[{"source":"pocgithub","id":"TailwindRG/cve-2026-0300-audit","title":"TailwindRG/cve-2026-0300-audit","date":"2026-05-06","url":"https://github.com/TailwindRG/cve-2026-0300-audit"},{"source":"pocgithub","id":"ashrafzaryouh/CVE-2026-0300","title":"ashrafzaryouh/CVE-2026-0300","date":"2026-05-06","url":"https://github.com/ashrafzaryouh/CVE-2026-0300"},{"source":"pocgithub","id":"matad0r-maghribi/CVE-2026-0300-PANOS","title":"matad0r-maghribi/CVE-2026-0300-PANOS","date":"2026-05-06","url":"https://github.com/matad0r-maghribi/CVE-2026-0300-PANOS"},{"source":"pocgithub","id":"mr-r3b00t/CVE-2026-0300","title":"mr-r3b00t/CVE-2026-0300","date":"2026-05-06","url":"https://github.com/mr-r3b00t/CVE-2026-0300"},{"source":"pocgithub","id":"p3Nt3st3r-sTAr/CVE-2026-0300-POC","title":"p3Nt3st3r-sTAr/CVE-2026-0300-POC","date":"2026-05-06","url":"https://github.com/p3Nt3st3r-sTAr/CVE-2026-0300-POC"},{"source":"pocgithub","id":"qassam-315/PAN-OS-User-ID-Buffer-Overflow-PoC","title":"qassam-315/PAN-OS-User-ID-Buffer-Overflow-PoC","date":"2026-05-06","url":"https://github.com/qassam-315/PAN-OS-User-ID-Buffer-Overflow-PoC"},{"source":"pocgithub","id":"shizuku198411/CVE-2026-0300","title":"shizuku198411/CVE-2026-0300","date":"2026-05-06","url":"https://github.com/shizuku198411/CVE-2026-0300"},{"source":"pocgithub","id":"lu4m575/CVE-2026-0300","title":"lu4m575/CVE-2026-0300","date":"2026-05-21","url":"https://github.com/lu4m575/CVE-2026-0300"},{"source":"pocgithub","id":"ridhinva/panos-captive-portal-rce","title":"ridhinva/panos-captive-portal-rce","date":"2026-05-22","url":"https://github.com/ridhinva/panos-captive-portal-rce"},{"source":"pocgithub","id":"sam00/POC-CVE-2026-0300-exploit","title":"sam00/POC-CVE-2026-0300-exploit","date":"2026-08-06","url":"https://github.com/sam00/POC-CVE-2026-0300-exploit"}],"products":[{"vendor":"palo alto networks","product":"cloud ngfw"},{"vendor":"palo alto networks","product":"pan-os"},{"vendor":"palo alto networks","product":"prisma access"},{"vendor":"paloaltonetworks","product":"pan-os"},{"vendor":"siemens","product":"ruggedcom ape1808"},{"vendor":"siemens","product":"ruggedcom_ape1808_firmware"}],"references":[{"url":"https://security.paloaltonetworks.com/CVE-2026-0300","tags":["vendor-advisory","Mitigation","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300","tags":["government-resource","US Government Resource"]},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-967325.html","tags":["Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-0300"},{"url":"https://github.com/advisories/GHSA-3vfh-3cpw-2378"}],"sources":{"cve":[{"id":"CVE-2026-0300","title":"PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal","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. \n\nThe 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.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.","status":"published","published":"2026-05-06T18:57:39.876Z","modified":"2026-10-15T01:11:55.163Z","cvss":[{"version":"4.0","score":9.3,"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","level":"critical","assessor":"cna"},{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:A/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","level":"high","assessor":"cna"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:20:13.587351Z"}],"euvd":[{"id":"EUVD-2026-27879","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. \n\nThe 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.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.","status":"published","published":"2026-05-06T18:57:39Z","modified":"2026-10-15T01:11:55Z","cvss":[{"version":"4.0","score":9.3,"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","level":"critical"}],"exploited_since":"2026-05-06","updated_at":"2026-11-02T17:27:06.951216Z"}],"ghsa":[{"id":"GHSA-3vfh-3cpw-2378","title":"A buffer overflow vulnerability in the User-ID™ Authentication Portal (aka Captive Portal)...","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. \n\nThe 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.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.","status":"published","published":"2026-05-06T21:31:36Z","modified":"2026-05-12T15:31:19Z","cvss":[{"version":"4.0","score":9.3,"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:C/RE:M/U:Red","level":"critical"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T15:08:04.468489Z"}],"kev":[{"id":"CVE-2026-0300","title":"Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability","description":"Palo Alto Networks PAN-OS contains an out-of-bounds write vulnerability in the User-ID Authentication Portal (aka Captive Portal) service that can allow an unauthenticated attacker to execute arbitrary code with root privileges on the PA-Series and VM-Series firewalls by sending specially crafted packets.","cwes":["CWE-787"],"kev":{"date_added":"2026-05-06","due_date":"2026-05-09","required_action":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented:  - Restrict User-ID Authentication Portal access to only trusted zones.  - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.","known_ransomware_use":"Unknown"},"updated_at":"2026-11-02T17:00:15.999436Z"}],"nvd":[{"id":"CVE-2026-0300","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. \n\nThe 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.\n\nPrisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.","status":"published","published":"2026-05-06T19:16:35.73Z","modified":"2026-10-26T19:10:00.163Z","cvss":[{"version":"4.0","score":9.3,"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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:C/RE:M/U:Red","level":"critical","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:12:17.418622Z"}]}}