Summary
| Parameter | Value |
|---|---|
| CVE ID | CVE-2026-0300 |
| Alert Source | CISA KEV - Active Exploitation |
| CVE Publication Year | 2026 |
| Date Published | 2026-05-06 |
| Vendor | Palo Alto Networks |
| Product | PAN-OS |
| CVSS Score | N/A (unknown) |
| EPSS Score | No data |
| CISA KEV | Yes - confirmed active exploitation |
| Ransomware | Not confirmed |
| Remediation Deadline | 2026-05-09 |
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.
Required Actions
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.
Who Is Affected?
This vulnerability affects PAN-OS by Palo Alto Networks. Check if your organization uses this software and requires updates.
Sources
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