Back to the CVE list
CVE-2026-0300 CISA KEV · Actively exploitedSuited to automated attack · CISA

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

CVSS score

9.3

EPSS probability

%31.7

Risk score

5.9

Published

5 mo ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Mitigation available

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented: - Restrict User-ID Authentication Portal access to only trusted zones. - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.

Impact on My Inventory

Only the personal products you have added to your account are assessed; an organisation's inventory does not appear here.

Checking session…

Vulnerability description

DayBreach CVE AI Research

CVE-2026-0300 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

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.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-0300 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1Palo Alto NetworksCloud NGFW View
2Palo Alto NetworksPAN-OS View
3Palo Alto NetworksPrisma Access View
4paloaltonetworkspan-os View
5paloaltonetworkspan-os View
6paloaltonetworkspan-os View
7paloaltonetworkspan-os View
8paloaltonetworkspan-os View
9paloaltonetworkspan-os View
10paloaltonetworkspan-os View
11paloaltonetworkspan-os View
12paloaltonetworkspan-os View
13paloaltonetworkspan-os View
14paloaltonetworkspan-os View
15paloaltonetworkspan-os View
16paloaltonetworkspan-os View
17paloaltonetworkspan-os View
18paloaltonetworkspan-os View
19paloaltonetworkspan-os View
20paloaltonetworkspan-os View
21paloaltonetworkspan-os View
22paloaltonetworkspan-os View
23paloaltonetworkspan-os View
24paloaltonetworkspan-os View
25paloaltonetworkspan-os View
26paloaltonetworkspan-os View
27paloaltonetworkspan-os View
28paloaltonetworkspan-os View
29paloaltonetworkspan-os View
30paloaltonetworkspan-os View
31paloaltonetworkspan-os View
32paloaltonetworkspan-os View
33paloaltonetworkspan-os View
34paloaltonetworkspan-os View
35paloaltonetworkspan-os View
36paloaltonetworkspan-os View
37paloaltonetworkspan-os View
38paloaltonetworkspan-os View
39paloaltonetworkspan-os View
40paloaltonetworkspan-os View
41paloaltonetworkspan-os View
42paloaltonetworkspan-os View
43paloaltonetworkspan-os View
44paloaltonetworkspan-os View
45paloaltonetworkspan-os View
46paloaltonetworkspan-os View
47paloaltonetworkspan-os View
48paloaltonetworkspan-os View
49paloaltonetworkspan-os View
50paloaltonetworkspan-os View
51paloaltonetworkspan-os View
52paloaltonetworkspan-os View
53paloaltonetworkspan-os View
54paloaltonetworkspan-os View
55paloaltonetworkspa-1410 View
56paloaltonetworkspa-1420 View
57paloaltonetworkspa-3410 View
58paloaltonetworkspa-3420 View
59paloaltonetworkspa-3430 View
60paloaltonetworkspa-3440 View
61paloaltonetworkspa-410 View
62paloaltonetworkspa-410r View
63paloaltonetworkspa-410r-5g View
64paloaltonetworkspa-415 View
65paloaltonetworkspa-415-5g View
66paloaltonetworkspa-440 View
67paloaltonetworkspa-445 View
68paloaltonetworkspa-450 View
69paloaltonetworkspa-450r View
70paloaltonetworkspa-450r-5g View
71paloaltonetworkspa-455 View
72paloaltonetworkspa-455-5g View
73paloaltonetworkspa-455r-5g View
74paloaltonetworkspa-460 View
75paloaltonetworkspa-501 View
76paloaltonetworkspa-505 View
77paloaltonetworkspa-510 View
78paloaltonetworkspa-520 View
79paloaltonetworkspa-540 View
80paloaltonetworkspa-5410 View
81paloaltonetworkspa-5420 View
82paloaltonetworkspa-5430 View
83paloaltonetworkspa-5440 View
84paloaltonetworkspa-5445 View
85paloaltonetworkspa-545-poe View
86paloaltonetworkspa-5450 View
87paloaltonetworkspa-550 View
88paloaltonetworkspa-5540 View
89paloaltonetworkspa-555-poe View
90paloaltonetworkspa-5550 View
91paloaltonetworkspa-5560 View
92paloaltonetworkspa-5570 View
93paloaltonetworkspa-5580 View
94paloaltonetworkspa-560 View
95paloaltonetworkspa-7500 View
96paloaltonetworkspa-7500-dpc-a View
97paloaltonetworksvm-100 View
98paloaltonetworksvm-300 View
99paloaltonetworksvm-50 View
100paloaltonetworksvm-500 View
101paloaltonetworksvm-700 View
102siemensruggedcom ape1808 firmware View
103siemensruggedcom ape1808 View
104Palo Alto NetworksPAN-OS View
Total affected vendors: 3|Products: 104

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
9.8CVSS V31CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HNVD
9.3CVSS V40CRITICALCVSS: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:RedNVD
9.3CVSS V4_0CRITICALCVSS: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:RedCVE CNA
8.7CVSS V4_0HIGHCVSS: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:RedCVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Workaround

Resmî yama doğrulanamadı; geçici azaltım veya workaround mevcut.

canonical

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Until the vendor releases an official fix, the following workaround should be implemented: - Restrict User-ID Authentication Portal access to only trusted zones. - Disable User-ID Authentication Portal if not required. 5/13/2026: Palo Alto has released a variety of patches. If these are relevant to your environment, please apply the designated patch.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

This CVE is marked as actively exploited in the CISA KEV catalogue, but no verified, downloadable public PoC or Metasploit module has been found yet. Evidence of active exploitation does not mean that public exploit code exists.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-0300 is associated with the following CWEs:

CWE-787: Out-of-bounds Write

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-0300 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

https://security.paloaltonetworks.com/CVE-2026-0300vendor-advisoryhttps://cert-portal.siemens.com/productcert/html/ssa-967325.htmlnvdhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-0300nvdCISA Known Exploited Vulnerabilities Catalogkev

CVSS Vector Radar Chart

9.3 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

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
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Geçici çözüm

Resmî yama doğrulanamadı; geçici azaltım veya workaround mevcut.

Follow the vendor

PA
Palo Alto Networks logo
Palo Alto Networks
P
paloaltonetworks logo
paloaltonetworks
S
siemens logo
siemens

Weakness Type (CWE & CAPEC)

CWE-787

Similar Vulnerabilities

Get this vulnerability through the API

Affected products, version ranges, exploitation status and patch information in a single request, with a free key.

Get a free keyDocumentation
curl -H "x-api-key: $DAYBREACH_API_KEY" \
  "https://api.daybreach.dev/api/v1/intel/cves/CVE-2026-0300"