CVE-2026-0300
Confirmed PUBLISHEDPAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal
1 day faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
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.
- CVE Published
- May 06, 2026
- Exploitation Reported
- Jun 01, 2026
- CVSS
- 9.3 Critical
- EPSS
- 36.2%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Siemens |
RUGGEDCOM APE1808
|
0 to < * |
Affected |
| Palo Alto Networks |
Cloud NGFW
|
All |
Unaffected |
| Palo Alto Networks |
PAN-OS
|
12.1.0 to < 12.1.7 Changed to unaffected at 12.1.7 Changed to unaffected at 12.1.4-h5 |
Affected |
| Palo Alto Networks |
PAN-OS
|
11.2.0 to < 11.2.12 Changed to unaffected at 11.2.12 Changed to unaffected at 11.2.10-h6 Changed to unaffected at 11.2.7-h13 Changed to unaffected at 11.2.4-h17 |
Affected |
| Palo Alto Networks |
PAN-OS
|
11.1.0 to < 11.1.15 Changed to unaffected at 11.1.15 Changed to unaffected at 11.1.13-h5 Changed to unaffected at 11.1.10-h25 Changed to unaffected at 11.1.7-h6 Changed to unaffected at 11.1.6-h32 Changed to unaffected at 11.1.4-h33 |
Affected |
| Palo Alto Networks |
PAN-OS
|
10.2.0 to < 10.2.18-h6 Changed to unaffected at 10.2.18-h6 Changed to unaffected at 10.2.16-h7 Changed to unaffected at 10.2.13-h21 Changed to unaffected at 10.2.10-h36 Changed to unaffected at 10.2.7-h34 |
Affected |
| Palo Alto Networks |
Prisma Access
|
All |
Unaffected |
CVE References
- Vendor Advisory — security.paloaltonetworks.com security.paloaltonetworks.com · Vendor Advisory https://security.paloaltonetworks.com/CVE-2026-0300
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Check enrichment artifacts for scanner coverage and available PoCs before rolling remediation validation.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 13:26 UTC |
| CISA | 2026-06-02 14:01 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitation Status
Exploited in the wild
Recorded 2026-06-01 13:26:25 UTC · CVE
Proof of concept available
Recorded 2026-05-21 20:39:21 UTC · GitHub
Weaknesses (CWE)
-
Out-of-bounds Write
Recent Mentions
Palo Alto Networks Security Advisories · May 28, 2026
Potential Proof of Concepts
These PoCs are unverified and could contain malware. Use at your own risk.
github · Created 2026-05-21 20:39:21 UTC · 0 stars
CVE-2026-0300 PAN-OS 12.1, 11.2, 11.1, 10.2
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:01 UTC about 2 months ago14:01 UTC · about 2 months ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
13:26 UTC about 2 months ago13:26 UTC · about 2 months ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
20:39 UTC 2 months ago20:39 UTC · 2 months ago
Public PoC available
Public proof-of-concept code published
-
18:57 UTC 3 months ago18:57 UTC · 3 months ago
CVE published
Vulnerability disclosed publicly
-
20:44 UTC 9 months ago20:44 UTC · 9 months ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2026-0300
{
"cve_id": "CVE-2026-0300",
"title": "PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-...",
"affected_vendor": "Palo Alto Networks",
"affected_product": "Cloud NGFW, PAN-OS, Prisma Access",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 9.3,
"epss_score": 0.36157,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}