CVE-2021-3063
PAN-OS: Denial-of-Service (DoS) Vulnerability in GlobalProtect Portal and Gateway Interfaces
- Published
- Updated
- Reserved
- Assigned by
- palo_alto
Description
An improper handling of exceptional conditions vulnerability exists in Palo Alto Networks GlobalProtect portal and gateway interfaces that enables an unauthenticated network-based attacker to send specifically crafted traffic to a GlobalProtect interface that causes the service to stop responding. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.21; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14-h4; PAN-OS 9.1 versions earlier than PAN-OS 9.1.11-h3; PAN-OS 10.0 versions earlier than PAN-OS 10.0.8-h4; PAN-OS 10.1 versions earlier than PAN-OS 10.1.3. Prisma Access customers are not impacted by this issue.
Timeline
ID reserved
By palo_alto
- 10 months later
· 10 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| palo_altoCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.93% · top 39% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Weakness
Affected products
- affected 8.1 – < 8.1.21
- affected 9.0 – < 9.0.14-h4
- affected 10.0 – < 10.0.8-h4
- affected 10.1 – < 10.1.3
- affected 9.1 – < 9.1.11-h3
Palo Alto Networks · Prisma Access
- unaffected 2.2 all
- unaffected 2.1 all
What to do
Solution: This issue is fixed in PAN-OS 8.1.21, PAN-OS 9.0.14-h4, PAN-OS 9.1.11-h3, PAN-OS 10.0.8-h4, PAN-OS 10.1.3, and all later PAN-OS versions.
Workaround: Enable signatures for Unique Threat IDs 91820 and 91855 on traffic destined for GlobalProtect interfaces to block attacks against CVE-2021-3063.
Exploitation: Palo Alto Networks is not aware of any malicious attempts to exploit this vulnerability.
References (1)
- https://security.paloaltonetworks.com/CVE-2021-3063 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-3063)Record last updated .