Threats / Palo Alto Networks / CVE-2026-0300
CVE-2026-0300
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Palo Alto Networks PAN-OS vulnerability
Palo Alto Networks PAN-OS contains an out-of-bounds write vulnerability in the Captive Portal service allowing unauthenticated attackers to execute arbitrary code with root privileges on PA-Series and VM-Series firewalls.
Verdict
Today item — known-exploited.
An unauthenticated remote attacker can exploit a memory corruption flaw in the User-ID Authentication Portal to achieve code execution at the highest privilege level, potentially compromising firewall integrity and all protected network traffic.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
6 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-06).
Probability (EPSS)
EPSS 0.3176 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Palo Alto Networks, PAN-OS. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-787 Out-of-bounds Write — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft malicious packets targeting the Captive Portal service without requiring authentication credentials.
Business
The firewall's perimeter defense is bypassed, eliminating a critical security boundary.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger an out-of-bounds write condition that corrupts memory and redirects execution flow to my payload.
Business
Arbitrary code execution at root level grants complete control over firewall operations and configuration.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistent access or exfiltrate sensitive firewall data and network traffic logs.
Business
Confidentiality and integrity of all network communications passing through the firewall are compromised.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05