PAN-OS User-ID Portal Buffer Overflow Enables Code Execution
Palo Alto Networks disclosed CVE-2026-0300, a buffer overflow in PAN-OS User-ID Authentication Portal being actively exploited to execute arbitrary code.
Sourceipa.go.jp — open the original
What to check
- Applies to
- The 1 CVE named below. Whether you run an affected version is not assessed: check the versions the source lists.
- Exploitation
- CISA lists CVE-2026-0300 as exploited in the wild.
Japan's IPA (Information-technology Promotion Agency) has issued a security alert regarding a critical vulnerability in Palo Alto Networks PAN-OS. The vulnerability, tracked as CVE-2026-0300, is a buffer overflow in the User-ID Authentication Portal component that allows remote attackers to execute arbitrary code on affected devices.
Palo Alto Networks has confirmed active exploitation of this vulnerability in the wild, raising immediate concern for organizations running affected PAN-OS versions. The vendor notes that Prisma Access, Cloud NGFW, and Panorama appliances are not impacted by this flaw.
IPA recommends that administrators immediately verify whether User-ID Authentication Portal is enabled on their systems and review access controls. Organizations should implement available workarounds and prepare for rapid deployment of patches once released by the vendor. Given the confirmed exploitation, this represents a time-sensitive threat requiring immediate attention from network security teams.
Mentioned in this report
Source reporting: https://www.ipa.go.jp/security/security-alert/2026/alert20260508.html
Free public brief. Slack alerts on the vendors you run come with the paid plans, and a new account gets three days of them, no card.
What this brief leaves out
This page is the free tier: the write-up, the severity, the names. In the app the same report carries live profiles of the CVEs it names. The paid plans add the security research and news reporting the free tier leaves out.
It sits in a corpus of 16,566 reports from 147 sources, 722 of them written in the last seven days, and it grows through the day.
A new account starts with three days of all of it, no card, then keeps the government and CERT reporting free. Slack alerts are a paid-plan feature: name the vendors you run and Slack hears about the reports that touch them, not the rest of the week's. Nothing is charged unless you subscribe.
Create a free account What it costs