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VulnerabilityPublished Updated

CVE-2026-0300: Palo Alto Networks PAN-OS · Out-of-bounds Write

Affects Palo Alto Networks PAN-OSSource CVE Database V5

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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

CVSS 4.0 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.
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:Red

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 6 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  4. Exploited in the wild: evidence found.

    Listed in CISA KEV the same day as disclosure

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by Palo Alto Networks, Inc.

    , 184 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. In Threat Radar

    record ingested

    , 9 minutes after disclosure

  4. , the same day as disclosure

  5. 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

ProductAffectedFixed in
Palo Alto NetworksPAN-OSAffected
  • >=12.1.0 <12.1.7
Fixed in
  • 12.1.7
Palo Alto NetworksPAN-OSAffected
  • >=11.2.0 <11.2.12
Fixed in
  • 11.2.12
Palo Alto NetworksPAN-OSAffected
  • >=11.1.0 <11.1.15
Fixed in
  • 11.1.15
Palo Alto NetworksPAN-OSAffected
  • >=10.2.0 <10.2.18-h6
Fixed in
  • 10.2.18-h6

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.

References

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