CVE-2026-0300
Palo Alto Networks · published 2026-05-06
Source record Collected from the National Vulnerability Database (NVD)
CISA Known Exploited Vulnerabilities
CISA lists this CVE as known exploited (added 2026-05-06).
- CISA's name for it: Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability
- 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.
- Known ransomware campaign use, per CISA: Unknown
Source: CISA KEV catalog (CC0 1.0).
Description
Description by Palo Alto Networks, Inc. via the CVE Program.
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.
Status at the source
- NVD status: Analyzed
Affected products, as the source lists them
| Vendor | Product | Versions |
|---|---|---|
| Palo Alto Networks | Cloud NGFW | All: unaffected |
| Palo Alto Networks | PAN-OS | 12.1.0 – before 12.1.7: affected 11.2.0 – before 11.2.12: affected 11.1.0 – before 11.1.15: affected 10.2.0 – before 10.2.18-h6: affected |
| Palo Alto Networks | Prisma Access | All: unaffected |
Added by siemens-SADP (Authorized Data Publisher)
| Vendor | Product | Versions |
|---|---|---|
| Siemens | RUGGEDCOM APE1808 | 0 – before *: affected |
Products named in NVD's CPE match criteria (2)
cpe:2.3:o:paloaltonetworks:pan-os:10.2.0:*:*:*:*:*:*:*cpe:2.3:o:siemens:ruggedcom_ape1808_firmware:-:*:*:*:*:*:*:*
DeSpy has not checked any unit, hardware revision or firmware. A product missing here is not a statement that it is unaffected.
Scores, as their sources published them
- CVSS 4.0: 9.3 CRITICAL — as published by Palo Alto Networks, Inc. (Secondary)
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 - CVSS 3.1: 9.8 CRITICAL — as published by NIST (Primary)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - SSVC — CISA's assessment (SSVC 2.0.3, CISA Coordinator): Exploitation: active · Automatable: yes · Technical impact: total
DeSpy does not score records. These are the sources' own values.
Weaknesses
Sources
References the source lists
- https://security.paloaltonetworks.com/CVE-2026-0300
- https://cert-portal.siemens.com/productcert/html/ssa-967325.html
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300
Source dates: published 2026-05-06, last changed 2026-06-17. DeSpy's copy of this version is dated 2026-09-28.
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