{"id":"CVE-2021-3055","aliases":["EUVD-2021-26407","GHSA-q695-424c-rgvg"],"status":"published","title":"PAN-OS: XML External Entity (XXE) Reference Vulnerability in the PAN-OS Web Interface","description":"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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.01073,"percentile":0.65379,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-611"],"published":"2021-09-08T17:10:22Z","modified":"2026-06-17T04:04:38Z","products":[{"vendor":"palo alto networks","product":"pan-os"},{"vendor":"paloaltonetworks","product":"pan-os"}],"references":[{"url":"https://security.paloaltonetworks.com/CVE-2021-3055","tags":["x_refsource_MISC","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-3055"},{"url":"https://github.com/advisories/GHSA-q695-424c-rgvg"}],"sources":{"cve":[{"id":"CVE-2021-3055","title":"PAN-OS: XML External Entity (XXE) Reference Vulnerability in the PAN-OS Web Interface","description":"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.","status":"published","published":"2021-09-08T17:10:22.809Z","modified":"2024-09-17T00:30:33.926Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-611"],"updated_at":"2026-11-02T14:33:03.671751Z"}],"euvd":[{"id":"EUVD-2021-26407","description":"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.","status":"published","published":"2021-09-08T17:10:22Z","modified":"2024-09-17T00:30:33Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:28:58.853192Z"}],"ghsa":[{"id":"GHSA-q695-424c-rgvg","title":"An improper restriction of XML external entity (XXE) reference vulnerability in the Palo Alto...","description":"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.","status":"published","published":"2022-05-24T19:13:19Z","modified":"2023-01-30T05:01:52Z","cwes":["CWE-611"],"updated_at":"2026-11-02T14:46:30.304291Z"}],"nvd":[{"id":"CVE-2021-3055","description":"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.","status":"published","published":"2021-09-08T17:15:12.337Z","modified":"2026-06-17T04:04:38.87Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:S/C:P/I:N/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-611"],"updated_at":"2026-11-02T14:06:58.502206Z"}]}}