{"id":"CVE-2026-0300","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-0300","generatedAt":"2026-10-28T14:18:30.034Z","title":"Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability","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.","published":"2026-05-06T19:16:36.000Z","lastModified":"2026-10-26T19:10:00.000Z","status":"Analyzed","sourceIdentifier":"psirt@paloaltonetworks.com","cvss":{"version":"4.0","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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-787"],"affected":["paloaltonetworks/pan-os","siemens/ruggedcom ape1808 firmware"],"epss":{"score":0.41714,"percentile":0.98679,"date":"2026-10-27","history":[{"date":"2026-10-25","score":0.41714,"percentile":0.98676}]},"kev":{"listed":true,"dateAdded":"2026-05-06","dueDate":"2026-05-09","knownRansomwareCampaignUse":"Unknown","notes":"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.\nhttps://security.paloaltonetworks.com/CVE-2026-0300 ; https://nvd.nist.gov/vuln/detail/CVE-2026-0300"},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 9 May 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.41714,"from":0.31725,"percentile":0.98676},"summary":"EPSS moved from 31.7% to 41.7% probability of exploitation in the next thirty days."}],"references":[{"url":"https://security.paloaltonetworks.com/CVE-2026-0300","tags":["Mitigation","Vendor Advisory"],"source":"psirt@paloaltonetworks.com"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-967325.html","tags":["Third Party Advisory"],"source":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-0300","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}