CVE-2026-0300
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- In the wild
- CISA lists this as exploited in real attacks. Treat as urgent.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- 2026-05-06 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
- PublishedDisclosed publicly on CVE.org and NVD
- 2026-05-09 Remediation deadlineCISA's due date for federal agencies to fix it
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
- Exploit odds: 41.7% in the next 30 days (EPSS).
- Severity: 9.3 CRITICAL (CVSS).
- Fix: a patch or advisory is linked.
- It meets the bar for Drop everything: critical, and exploited or very likely to be.
Details
- Published
- Last modified
- Added to CISA KEV
- 2026-05-06
- Exploit probability
- 41.7% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Analyzed
Affected
- Paloaltonetworks pan-os 10.2.0
- Paloaltonetworks pan-os 10.2.1
- Paloaltonetworks pan-os 10.2.2
- Paloaltonetworks pan-os 10.2.3
- Paloaltonetworks pan-os 10.2.4
- Paloaltonetworks pan-os 10.2.5
- Paloaltonetworks pan-os 10.2.6
- Paloaltonetworks pan-os 10.2.7
Attack profile CVSS 4.0 · 9.3
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw 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
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-0300.md and follow it. Check whether this project is affected by CVE-2026-0300. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
