Security readout for executives and security teams
Plain-English summary
This is a remote availability issue in Palo Alto Networks PAN-OS GlobalProtect portal and gateway interfaces. An unauthenticated attacker who can reach the interface could make GlobalProtect stop responding; repeated activity can restart the device and place it into maintenance mode. The business risk is VPN and firewall service disruption, not data theft.
Executive priority
Treat this as a high-priority availability risk for VPN and firewall operations, especially on internet-facing GlobalProtect deployments. Prioritize upgrades on exposed affected versions because exploitation requires no authentication and can disrupt access for all dependent users.
Technical view
CVE-2021-3063 is CWE-755 improper handling of exceptional conditions in PAN-OS GlobalProtect portal and gateway interfaces. It is CVSS 3.1 7.5, network exploitable, low complexity, no privileges or user interaction, with high availability impact and no stated confidentiality or integrity impact.
Likely exposure
Exposure is most likely where affected PAN-OS GlobalProtect portal or gateway interfaces are reachable by untrusted networks. Affected trains are PAN-OS 8.1, 9.0, 9.1, 10.0, and 10.1 before the listed fixed versions. The source states Prisma Access customers are not impacted.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. The vendor description supports unauthenticated network-based denial of service against reachable GlobalProtect interfaces, with repeated attempts potentially causing device restart and maintenance mode.
Researcher notes
The evidence supports denial of service only. The vulnerability affects GlobalProtect portal and gateway handling of exceptional conditions. No exploit code, active exploitation, or data compromise evidence is included in the provided bundle. Prisma Access is explicitly described as not impacted despite appearing in affected metadata.
Mitigation direction
- Upgrade PAN-OS 8.1 to 8.1.21 or later.
- Upgrade PAN-OS 9.0 to 9.0.14-h4 or later.
- Upgrade PAN-OS 9.1 to 9.1.11-h3 or later.
- Upgrade PAN-OS 10.0 to 10.0.8-h4 or later.
- Upgrade PAN-OS 10.1 to 10.1.3 or later.
- Follow Palo Alto Networks advisory guidance for deployment-specific remediation.
Validation and detection
- Inventory PAN-OS versions on devices running GlobalProtect portal or gateway interfaces.
- Confirm whether GlobalProtect interfaces are reachable from untrusted networks.
- Verify upgraded devices meet or exceed the fixed PAN-OS versions.
- Check operational history for unexpected restarts, service stops, or maintenance-mode events.
- Confirm Prisma Access environments are excluded only where vendor conditions match.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-755: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-3063 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://security.paloaltonetworks.com/CVE-2021-3063CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Handling of Exceptional Conditions
Improper Handling of Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.