Palo Alto Networks Security Advisories / CVE-2021-3053

CVE-2021-3053 PAN-OS: Exceptional Condition Denial-of-Service (DoS)

Severity 7.5 · HIGH
Attack Vector NETWORK
Attack Complexity LOW
Confidentiality Impact NONE
Privileges Required NONE
Integrity Impact NONE
User Interaction NONE
Availability Impact HIGH


An improper handling of exceptional conditions vulnerability exists in the Palo Alto Networks PAN-OS dataplane that enables an unauthenticated network-based attacker to send specifically crafted traffic through 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 9.1.9;

PAN-OS 10.0 versions earlier than PAN-OS 10.0.5.

This issue does not affect Prisma Access.

Product Status

PAN-OS 10.1None10.1.*
PAN-OS 10.0< 10.0.5>= 10.0.5
PAN-OS 9.1< 9.1.9>= 9.1.9
PAN-OS 9.0< 9.0.14>= 9.0.14
PAN-OS 8.1< 8.1.20>= 8.1.20

Required Configuration for Exposure

This issue is applicable only if GTP security is configured on the firewall.

Severity: HIGH

CVSSv3.1 Base Score: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Exploitation Status

Palo Alto Networks is not aware of any malicious exploitation of this issue.

Weakness Type

CWE-755 Improper Handling of Exceptional Conditions


This issue is fixed in PAN-OS 8.1.20, PAN-OS 9.0.14, PAN-OS 9.1.9, PAN-OS 10.0.5, and all later PAN-OS versions.

Workarounds and Mitigations

Enable signatures for Unique Threat ID 91593 on traffic processed by the firewall to block attacks against CVE-2021-3053.


This issue was found by Nicholas Newsom of Palo Alto Networks during internal security review.


Added required configuration for exposure and threat prevention workaround for the vulnerability
Initial publication
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