CVE-2026-0300
Out-of-bounds Write in Palo Alto Networks PAN-OS. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 6 May 2026.
- Product
- Palo Alto Networks PAN-OS
- Added to CISA's catalog
- Federal fix-by date
- Ransomware
- No known use in ransomware campaigns
- Vendor advisories
- Sources
- CISA’s catalog, NVD entry
CISA’s 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.
More from Palo Alto Networks this year.
- CVE-2026-0322 Code Injection, added
- CVE-2026-0257 Authentication Bypass, added
Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 4 November 2026.