CVE-2026-0300
Published: 06 May 2026
Summary
CVE-2026-0300 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Paloaltonetworks Pan-Os. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 5.5% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Out-of-bounds writes that corrupt control flow or inject shellcode are rendered non-executable by the same memory protections.
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…
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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.
Deeper analysisAI
Automated synthesis unavailable for this CVE.
Details
- CWE(s)
- KEV Date Added
- 06 May 2026