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CRITICAL CISA KEV

CVE-2026-0300

CVSS v3

9.8

CRITICAL

EPSS Score

31.7 %

exploit probability, as of 2026-10-19

CISA KEV

Yes

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • ICSA-26-139-02 CISA1 known affected

    Siemens RUGGEDCOM APE1808 Devices

    RUGGEDCOM APE1808

  • SSA-967325 Siemens ProductCERT1 known affected

    SSA-967325: Multiple Vulnerabilities in Palo Alto Networks PAN-OS before V11.2.10-h7 on RUGGEDCOM APE1808 Devices

    RUGGEDCOM APE1808 with Palo Alto Networks Virtual NGFW with User-ID™ Authentication Portal configured and interface management profile with response pages enabled

Full record on 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 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.

CISA Known Exploited Vulnerability

Date Added
2026-05-06
Patch Due Date
2026-05-09
Ransomware Use
Unknown

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2026-05-06

Frequently asked questions

What is CVE-2026-0300?

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.

Is CVE-2026-0300 actively exploited?

Yes. CVE-2026-0300 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2026-05-09.

What is the CVSS score for CVE-2026-0300?

CVE-2026-0300 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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