CVE-2026-0300

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

At a glance

Severity: CRITICAL 9.3
Exploitation: Known exploited (CISA KEV) · added 2026-05-06
Exploited per ENISA since 2026-05-06
EPSS: EPSS 41.71 % · percentile 99 (2026-10-27)
State: PUBLISHED
Published: 2026-05-06
Updated: 2026-10-15
Assigner: palo_alto
NVD status: Analyzed

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.

Scores

Version	Score	Vector	Scored by
CVSS 4.0	CRITICAL 9.3	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/AU:Y/R:U/V:C/RE:M/U:Red	palo_alto
CVSS 4.0	HIGH 8.7	CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/E:A/AU:Y/R:U/V:C/RE:M/U:Red	palo_alto
CVSS 4.0	CRITICAL 9.3	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	NVD · psirt@paloaltonetworks.com (Secondary)
CVSS 3.1	CRITICAL 9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-787

European references

ENISA EUVD · EUVD-2026-27879
GCVE · GCVE-0-2026-0300

CERT-FR advisories

CERTFR-2026-AVI-0537 — Vulnérabilité dans Palo Alto Networks User-ID Authentication Portal · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:o:paloaltonetworks:pan-os:10.2.0:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.1:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.2:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.3:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.4:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.5:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.6:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:-:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h1:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h12:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h16:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h19:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h21:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h24:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h3:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h32:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h6:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.7:h8:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.8:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.9:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:-:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h10:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h12:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h14:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h17:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h18:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h2:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h21:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h27:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h3:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h30:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h31:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h4:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h5:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h7:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.10:h9:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.11:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.12:*:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.13:-:*:*:*:*:*:*
cpe:2.3:o:paloaltonetworks:pan-os:10.2.13:h1:*:*:*:*:*:*
+123 more

Affected products

Product	Versions
Palo Alto Networks · Cloud NGFW	unaffected All
Palo Alto Networks · PAN-OS	affected 12.1.0 < 12.1.7 ; affected 11.2.0 < 11.2.12 ; affected 11.1.0 < 11.1.15 ; affected 10.2.0 < 10.2.18-h6
Palo Alto Networks · Prisma Access	unaffected All

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
CISA Known Exploited Vulnerabilities	CC0 1.0
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD