Palo Alto Networks PAN-OS Reflected Amplification Denial-of-Service Vulnerability
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…
Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.
Exploitation probability EPSS · FIRST
Exploitation signals 3 / 5
- KEV catalog (CISA)22 Aug 2022
- Exploited in EUVD (ENISA)22 Aug 2022
- Used by ransomwareno
- EPSS above 10 %2.7%
- No account, over the networkyes
What to do
Fix
Apply the vendor’s fix as soon as it is available.
CISA guidance: Apply updates per vendor instructions.
Meanwhile
Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.
Manufacturers (CRA)
Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained
Description ENISA EUVD
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.
Affected products
- 10.1 <10.1.6-h6
- 8.1 <8.1.23-h1
- 10.2 <10.2.2-h2
- 10.0 <10.0.11-h1
- 9.0 <9.0.16-h3
- 9.1 <9.1.14-h4
Open source packages OSV
Affected libraries according to OSV, with fixed versions.
Timeline
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Published
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Exploitation reported (ENISA)
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Added to the KEV catalog
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CISA remediation due date
References
Other exploited vulnerabilities from the same vendor
- CVE-2026-0322Palo Alto Networks PAN-OS Code Injection Vulnerability4.7 · Rising fast
- CVE-2026-0257Palo Alto Networks PAN-OS Authentication Bypass Vulnerability9.0 · Actively exploited
- CVE-2026-0300Palo Alto Networks PAN-OS Out-of-bounds Write Vulnerability7.4 · Background exploitation
- CVE-2025-0111Palo Alto Networks PAN-OS File Read Vulnerability4.1 · Background exploitation
- CVE-2025-0108Palo Alto Networks PAN-OS Authentication Bypass Vulnerability8.9 · Background exploitation
- CVE-2024-3393Palo Alto Networks PAN-OS Malicious DNS Packet Vulnerability6.8 · Background exploitation