CVE-2021-3048Network attack vector

Traffic outage via invalid EDL URL processing

Published Aug 11, 2021 · Updated Sep 16, 2024

Improper input validation in PAN-OS allows remote attackers to interrupt firewall traffic through a malformed URL in an EDL. The Device Server daemon fails to validate invalid URL entries while processing the list and stops responding, so later configuration commits fail. Exposure requires an EDL with URL entries; domain-only or IP-only lists are not affected, and a subsequent firewall restart stops traffic processing.

CVSS severity5.9
Medium
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in PAN-OS allows remote attackers to interrupt firewall traffic through a malformed URL in an EDL. The Device Server daemon fails to validate invalid URL entries while processing the list and stops responding, so later configuration commits fail. Exposure requires an EDL with URL entries; domain-only or IP-only lists are not affected, and a subsequent firewall restart stops traffic processing.

The record

CVE
CVE-2021-3048
Published
Aug 11, 2021
Updated
Sep 16, 2024
Vendor
Palo Alto Networks
Product
PAN-OS
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0 <10.0.5 changes=[{"at":"10.0.5","status":"unaffected"}]
  2. Affected versionversion=9.0 <9.0.14 changes=[{"at":"9.0.14","status":"unaffected"}]
  3. Affected versionversion=9.1 <9.1.9 changes=[{"at":"9.1.9","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Palo Alto Networks · PAN-OSversion=10.0 <10.0.5 changes=[{"at":"10.0.5","status":"unaffected"}]; version=9.0 <9.0.14 changes=[{"at":"9.0.14","status":"unaffected"}]; version=9.1 <9.1.9 changes=[{"at":"9.1.9","status":"unaffected"}]

Published CVSS scores

5.9Palo Alto NetworksCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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