CVE-2026-0300: Palo Alto Networks PAN-OS · Out-of-bounds Write
Affects Palo Alto Networks PAN-OSSource CVE Database V5
Exploited in the wild · KEV due 9 May 2026 · 41% EPSS · fixed in 12.1.7 : patch Palo Alto Networks PAN-OS now.
Data as of 30 Oct 2026, 11:34 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- EPSS
- 41.7% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 12.1.7, 11.2.12, 11.1.15 +1
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:RedExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 6 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: evidence found.
Listed in CISA KEV the same day as disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by Palo Alto Networks, Inc.
, 184 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 9 minutes after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed
, the same day as disclosure
KEV remediation due
US federal deadline
, 3 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade Palo Alto Networks PAN-OS to 12.1.7, 11.2.12, 11.1.15 or 10.2.18-h6.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Palo Alto NetworksPAN-OS | Affected
| Fixed in
|
| Palo Alto NetworksPAN-OS | Affected
| Fixed in
|
| Palo Alto NetworksPAN-OS | Affected
| Fixed in
|
| Palo Alto NetworksPAN-OS | Affected
| Fixed in
|
Check the firmware or software version for Palo Alto Networks PAN-OS in the device's admin interface against the vendor advisory.
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.