CVE-2022-0028 — PAN-OS: Reflected Amplification Denial-of-Service (DoS) Vulnerability in URL Filtering

Summary

A PAN-OS URL filtering policy misconfiguration could allow a network-based attacker to conduct reflected and amplified TCP denial-of-service (RDoS) attacks. The DoS attack would appear to originate from a Palo Alto Networks PA-Series (hardware), VM-Series (virtual) and CN-Series (container) firewall against an attacker-specified target. To be misused by an external attacker, the firewall configuration must have a URL filtering profile with one or more blocked categories assigned to a source zone that has an external facing interface. This configuration is not typical for URL filtering and, if set, is likely unintended by the administrator. If exploited, this issue would not impact the confidentiality, integrity, or availability of our products. However, the resulting denial-of-service (DoS) attack may help obfuscate the identity of the attacker and implicate the firewall as the source of the attack. We have taken prompt action to address this issue in our PAN-OS software. All software updates for this issue are expected to be released no later than the week of August 15, 2022. This issue does not impact Panorama M-Series or Panorama virtual appliances. This issue has been resolved for all Cloud NGFW and Prisma Access customers and no additional action is required from them.

Weakness: CWE-406

Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.

Affected and fixed versions

Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.

Remediation

Known exploitation

2% probability of exploitation in the next 30 days (percentile 83%).

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CERT-FR

No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.

Timeline

1. 10 Aug 2022Published by the source
2. 22 Aug 2022Added to CISA KEV
3. 12 Sept 2022CISA remediation due date
4. 17 Jun 2026Source record last modified
5. 29 Sept 2026EPSS score computed
6. 1 Oct 2026Last verified by Patcharo

Official sources

• Palo Alto Networks (CVE record)retrieved 1 Oct 2026 at 09:29 UTC
• CISA Known Exploited Vulnerabilitiesretrieved 1 Oct 2026 at 09:28 UTC
• NVDretrieved 27 Sept 2026 at 23:44 UTC
• FIRST EPSSretrieved 30 Sept 2026 at 00:17 UTC

Palo Alto Networks · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS