CVE-2022-0028
CVE-2022-0028 is a security flaw in Palo Alto Networks PAN-OS, the operating system on Palo Alto Networks’ firewalls. Attackers can crash Palo Alto Networks PAN-OS or stop it working. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 22 Aug 2022.[1]
Palo Alto Networks PAN-OS is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 8.1.23-h1, 9.0.16-h3, 9.1.14-h4 and 10.0.11-h1 and others.
Description
CISA calls it a reflected amplification denial-of-service in Palo Alto Networks PAN-OS. In its words: “A Palo Alto Networks PAN-OS URL filtering policy misconfiguration could allow a network-based attacker to conduct reflected and amplified TCP denial-of-service (RDoS) attacks.”[1]
The CVE record adds: “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…”[2]
The underlying weakness is CWE-940, in MITRE’s list of common software weaknesses.
It scores 8.6 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| PAN-OS | 8.1.23-h1 |
| PAN-OS | 9.0.16-h3 |
| PAN-OS | 9.1.14-h4 |
| PAN-OS | 10.0.11-h1 |
| PAN-OS | 10.1.6-h6 |
| PAN-OS | 10.2.2-h2 |
| pan-os | 8.1.23-h |
| pan-os | 9.0.16-h3 |
Most families won’t have Palo Alto Networks PAN-OS; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 22 Aug 2022, 12 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 12 Sep 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 3%. That’s in the top 15% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Palo Alto Networks has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Palo Alto Networks PAN-OS is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 8.1.23-h1, 9.0.16-h3, 9.1.14-h4 and 10.0.11-h1 and others), or not in use. CISA gave US government agencies until 12 Sep 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 8.6.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 3%.[4] |
See also
Other Palo Alto Networks PAN-OS flaws
- CVE-2026-0322: code injection ·
- CVE-2026-0257: authentication bypass ·
- CVE-2026-0300: out-of-bounds write ·
- CVE-2025-0111: file read ·
- CVE-2025-0108: authentication bypass ·
- CVE-2024-3393: malicious DNS packet ·
Other Palo Alto Networks flaws
- CVE-2024-9465, Palo Alto Networks Expedition: SQL injection ·
- CVE-2024-9463, Palo Alto Networks Expedition: OS command injection ·
- CVE-2024-5910, Palo Alto Networks Expedition: missing authentication ·
Similar flaws
- CVE-2025-61932, Motex LANSCOPE Endpoint Manager: improper verification of source of a communication channel ·
Every Palo Alto Networks flaw on CISA’s list · Everything added in August 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Palo Alto Networks PAN-OS Reflected Amplification Denial-of-Service Vulnerability”. Known Exploited Vulnerabilities Catalog, added 22 Aug 2022.
- ^ National Institute of Standards and Technology. “CVE-2022-0028 Detail”. National Vulnerability Database, published 10 Aug 2022.
- ^ Palo Alto Networks. Advisories and fixes: security.paloaltonetworks.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.027, percentile 85.9, 31 Oct 2026.
- CVE Program. “CVE-2022-0028”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.