Summary
generated automatically from NVD dataCVE-2026-0300 is a buffer overflow (CWE-787) in the User-ID Authentication Portal (Captive Portal) service of Palo Alto Networks PAN-OS, affecting PA-Series and VM-Series firewalls. An unauthenticated attacker can send specially crafted packets to execute arbitrary code with root privileges. It is rated CVSS 9.8 (CRITICAL) and is listed in the CISA KEV catalog, which indicates active exploitation. The description says risk is greatly reduced by restricting portal access to trusted internal IP addresses.
NVD 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.
⚠️ Actively exploited — CISA KEV
This CVE was added to CISA's Known Exploited Vulnerabilities catalog on 2026-05-06. It is confirmed exploited in the wild and must be patched as a priority.
Remediation deadline (US federal agencies): 2026-05-09
EPSS · FIRST.org
31.7%probability of exploitation in the next 30 days
Higher than 98% of scored CVEs
EPSS (Exploit Prediction Scoring System) estimates, from observed exploitation activity, how likely a CVE is to be exploited in the next 30 days. It complements CVSS, which measures severity, not likelihood. Score of 2026-10-16, recomputed daily by FIRST.org.
In-depth analysis on cveo.tech
We've published a detailed analysis of this CVE — exploitation, IOCs and mitigation.
CVSS v3.1 Score
Information
- Published
- 6 mai 2026
- Updated
- 17 juin 2026
- Status
- Analyzed
- Source
- psirt@paloaltonetworks.com
Affected products
Weaknesses (CWE)
References (3)
- https://security.paloaltonetworks.com/CVE-2026-0300MitigationVendor Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-967325.htmlThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300US Government Resource
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