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Pan OsOperating system · Paloaltonetworks

CVE-2021-3053

HIGH · 7.5 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 8.1.20 / 9.0.14 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the PAN-OS dataplane allows an unauthenticated remote attacker to send specially crafted traffic that triggers improper exception handling, causing the firewall service to crash. Repeated exploitation results in sustained denial of service as the device repeatedly restarts and enters maintenance mode.

MitigationUpgrade PAN-OS to version 8.1.20, 9.0.14, 9.1.9, 10.0.5 or later. Apply the update during a planned maintenance window and verify firewall services resume normally post-upgrade.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Pan OsOperating system
Affected:>= 8.1.0, < 8.1.20>= 9.0.0, < 9.0.14>= 9.1.0, < 9.1.9>= 10.0.0, < 10.0.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed PAN-OS version
    Access the firewall management interface or use the command: show system info or request system info. Look for the 'sw-version' or 'PAN-OS' field showing the exact version number.
    Affected if The installed version falls within any of these ranges: 8.1.0 to 8.1.19, 9.0.0 to 9.0.13, 9.1.0 to 9.1.8, or 10.0.0 to 10.0.4.
  2. Check for recent system restarts
    Review system logs using: request log system dump or check the System Logs for 'system restart' or 'maintenance mode' entries occurring without scheduled maintenance.
    Affected if The device shows unexpected reboots or entries into maintenance mode that were not planned.
  3. Verify firewall service status
    Access the management interface and check the Dashboard or use: show high-availability state to confirm all firewall services are running normally without unexpected down states.
    Affected if Firewall services show as down, crashed, or the dataplane indicates abnormal status.
  4. Review dataplane crash logs
    Use the command: debug logdump to search for exception handling errors or crash signatures related to specially crafted traffic processing.
    Affected if Logs show repeated crash events related to exception handling failures in the dataplane.

You are affected if your PAN-OS version is 8.1.0-8.1.19, 9.0.0-9.0.13, 9.1.0-9.1.8, or 10.0.0-10.0.4 AND you observe unexplained service crashes, restarts, or maintenance mode entries.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.1.20 / 9.0.14 / 9.1.9 or later
Fixed in 8.1.209.0.149.1.9
Interim mitigation

Upgrade PAN-OS to version 8.1.20, 9.0.14, 9.1.9, 10.0.5 or later. Apply the update during a planned maintenance window and verify firewall services resume normally post-upgrade.

Recommended fix High confidence

Upgrade to PAN-OS 8.1.20 (or later 8.1.x), 9.0.14 (or later 9.0.x), 9.1.9 (or later 9.1.x), or 10.0.5 (or later 10.0.x) based on your current branch

  1. 1. Identify the current PAN-OS version by navigating to Device > Setup > Operations or using 'show system info' in the CLI.
  2. 2. Determine which upgrade path applies based on current version: 8.1.x → 8.1.20+, 9.0.x → 9.0.14+, 9.1.x → 9.1.9+, or 10.0.x → 10.0.5+.
  3. 3. Download the appropriate PAN-OS upgrade image from the Palo Alto Networks Customer Support Portal (https://support.paloaltonetworks.com).
  4. 4. Upload the upgrade file via Panorama (if managed) or directly to the firewall via Device > Software or SCP/SFTP.
  5. 5. Before upgrading, back up the current configuration via Device > Setup > Operations > Save Named Configuration Snapshot.
  6. 6. Initiate the upgrade: Device > Software > Install (or 'request system software install' in CLI).
  7. 7. After installation completes, verify the new version via 'show system info' and confirm all services are running normally.
  8. 8. Validate that the firewall is no longer vulnerable by confirming the installed version meets or exceeds the fixed release for your branch.
Caveat Review Palo Alto Networks Release Notes for your target version to check for configuration or feature changes; always test in a non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Pan Os Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,150
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-3053 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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