CVE-2021-3055

6.5 MEDIUM 1% exploit odds Fix listed

What it is

An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto Networks PAN-OS web interface enables an authenticated administrator to read any arbitrary file from the file system and send a specifically crafted request to 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 9.1.10; PAN-OS 10.0 versions earlier than PAN-OS 10.0.6. This issue does not affect Prisma Access.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of data exposure, service disruption.
Exploit odds: 1.1% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-09-08 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 04:04 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.1% in the next 30 days (EPSS).
Severity: 6.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-09-08 17:15 UTC
Last modified: 2026-06-17 04:04 UTC
Exploit probability: 1.1% · EPSS, next 30 days
Weakness: CWE-611 · XML external entity
Record status: Modified

Affected

Paloaltonetworks pan-os < 8.1.20
Paloaltonetworks pan-os < 9.0.14
Paloaltonetworks pan-os < 9.1.10
Paloaltonetworks pan-os < 10.0.6

Attack profile CVSS 3.1 · 6.5

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: High

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-3055.md and follow it. Check whether this project is affected by CVE-2021-3055. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record