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High · 8.7 Known exploited Public exploit CVE-2026-0300 EUVD-2026-27879GHSA-3vfh-3cpw-2378

PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal

Published May 6, 2026 · Updated Oct 15, 2026 · Assigned by palo_alto

Vendor: Palo Alto Networks Product: Cloud NGFW Product: PAN-OS Product: Prisma Access Category: Network devices

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.

The 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.

Prisma Access, Cloud NGFW and Panorama appliances are not impacted by this vulnerability.

Affected products

VendorProductAffectedFixed
Palo Alto Networks Cloud NGFW — All
Palo Alto Networks PAN-OS 12.1.0 – < 12.1.7, 11.2.0 – < 11.2.12, 11.1.0 – < 11.1.15, 10.2.0 – < 10.2.18-h6 12.1.7
Palo Alto Networks Prisma Access — All

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 10 repositories

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 4

References