CVE-2021-3055
PAN-OS: XML External Entity (XXE) Reference Vulnerability in the PAN-OS Web Interface
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to the firewall that causes the service to crash. 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 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
PAN-OS: XML External Entity (XXE) Reference Vulnerability in the PAN-OS Web Interface
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to the firewall that causes the service to crash. 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 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.
- Record
CVE-2021-3055- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H - Weakness
- CWE-611
- Updated
- 2026-11-02
EUVDEUVD-2021-26407
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to the firewall that causes the service to crash. 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 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.
- Record
EUVD-2021-26407- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-q695-424c-rgvgNo score
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto...
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to the firewall that causes the service to crash. 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 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.
- Record
GHSA-q695-424c-rgvg- Weakness
- CWE-611
- Updated
- 2026-11-02
NVD
An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to the firewall that causes the service to crash. 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 8.1.20; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14; PAN-OS 9.1 versions earlier than PAN-OS 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.
- Record
CVE-2021-3055- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:S/C:P/I:N/A:C - Weakness
- CWE-611
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3055 is a medium vulnerability (CVSS 6.5) in Palo Alto Networks Pan-os, published September 8, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.07%, the 65th percentile. No source names a fixed version.