CVE-2026-0300— PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal
Quick assessment
Affected
Palo Alto Networks Cloud NGFW
Exploitation
Confirmed exploitation in the wild; remediate immediately
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Palo Alto Networks PAN-OS是美国Palo Alto Networks公司的一套为其防火墙设备开发的操作系统。 Palo Alto Networks PAN-OS存在缓冲区错误漏洞，该漏洞源于User-ID Authentication Portal服务在处理特定数据包时的边界检查不足。未经身份认证的攻击者可通过向目标防火墙的User-ID Authentication Portal服务发送特制的数据包，触发缓冲区溢出，从而在目标设备上以 root 权限执行任意代码。
In-the-Wild Activity Observed
cisa_kev · confirmed
Possible ATT&CK Techniques 3 AI
T1548 · Abuse Elevation Control Mechanism T1068 · Exploitation for Privilege Escalation T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 6
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Palo Alto Networks | Cloud NGFW | All |
unaffected |
| Palo Alto Networks | PAN-OS | 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 |
affected | ||
| Palo Alto Networks | Prisma Access | All |
unaffected |
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I. Basic Information for CVE-2026-0300
Vulnerability Information
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Vulnerability Title
PAN-OS: Unauthenticated user initiated Buffer Overflow Vulnerability in User-ID™ Authentication Portal
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存写
Source: CVE Program / CVE List V5
Vulnerability Title
Palo Alto Networks PAN-OS 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Palo Alto Networks PAN-OS是美国Palo Alto Networks公司的一套为其防火墙设备开发的操作系统。 Palo Alto Networks PAN-OS存在缓冲区错误漏洞，该漏洞源于User-ID Authentication Portal服务在处理特定数据包时的边界检查不足。未经身份认证的攻击者可通过向目标防火墙的User-ID Authentication Portal服务发送特制的数据包，触发缓冲区溢出，从而在目标设备上以 root 权限执行任意代码。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Shenlong Deep Dive — AI Deep Analysis
10-question deep dive: root cause, exploitation, mitigation, urgency. Read summary free, full version requires login.
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Palo Alto Networks | Cloud NGFW | - | - |
|
| Palo Alto Networks | PAN-OS | 12.1.0 ~ 12.1.7 |
cpe:2.3:o:palo_alto_networks:pan-os:12.1.6:*:*:*:*:*:*:*
|
|
| Palo Alto Networks | Prisma Access | - | - |
|
II. Public POCs for CVE-2026-0300
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POC
Premium
default-local-hunyuan-2.0-instruct
· 9377 chars
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III. Intelligence Information for CVE-2026-0300
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Vendor Advisories for CVE-2026-0300 (1)
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V. Comments for CVE-2026-0300
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