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CVE-2020-2021KEVRansomware

PAN-OS: Authentication Bypass in SAML Authentication

Severity
Critical10CVSS 3.1, Critical
EPSS
4%
Published
29 Jun 2020
Updated
17 Jun 2026

Description

Title, description and vendor guidance are quoted from the source records.

When Security Assertion Markup Language (SAML) authentication is enabled and the 'Validate Identity Provider Certificate' option is disabled (unchecked), improper verification of signatures in PAN-OS SAML authentication enables an unauthenticated network-based attacker to access protected resources. The attacker must have network access to the vulnerable server to exploit this vulnerability. This issue affects PAN-OS 9.1 versions earlier than PAN-OS 9.1.3; PAN-OS 9.0 versions earlier than PAN-OS 9.0.9; PAN-OS 8.1 versions earlier than PAN-OS 8.1.15, and all versions of PAN-OS 8.0 (EOL). This issue does not affect PAN-OS 7.1. This issue cannot be exploited if SAML is not used for authentication. This issue cannot be exploited if the 'Validate Identity Provider Certificate' option is enabled (checked) in the SAML Identity Provider Server Profile. Resources that can be protected by SAML-based single sign-on (SSO) authentication are: GlobalProtect Gateway, GlobalProtect Portal, GlobalProtect Clientless VPN, Authentication and Captive Portal, PAN-OS next-generation firewalls (PA-Series, VM-Series) and Panorama web interfaces, Prisma Access In the case of GlobalProtect Gateways, GlobalProtect Portal, Clientless VPN, Captive Portal, and Prisma Access, an unauthenticated attacker with network access to the affected servers can gain access to protected resources if allowed by configured authentication and Security policies. There is no impact on the integrity and availability of the gateway, portal or VPN server. An attacker cannot inspect or tamper with sessions of regular users. In the worst case, this is a critical severity vulnerability with a CVSS Base Score of 10.0 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N). In the case of PAN-OS and Panorama web interfaces, this issue allows an unauthenticated attacker with network access to the PAN-OS or Panorama web interfaces to log in as an administrator and perform administrative actions. In the worst-case scenario, this is …

Weakness: CWE-347

Known exploited

Added to CISA KEV on 25 Mar 2022

Federal remediation due date: 15 Apr 2022

Known use in ransomware campaigns

Required action: Apply updates per vendor instructions.

Exploit prediction

4% probability of exploitation in the next 30 days (percentile 91%).

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

What the source states, per branch

Versions matched by Patcharo

Palo Alto Networks PAN-OSSource: Palo Alto Networks (CVE record)

BranchAffectedFixed in
9.1
>= 9.1.0, < 9.1.3
9.1.3
9.0
>= 9.0.0, < 9.0.9
9.0.9
8.1
>= 8.1.0, < 8.1.15
8.1.15
8.0
>= 8.0.0
No fix published
7.1Not affected

Versions not listed are not assessed (shown as Unknown).

Workaround / Vendor remediation

Workaround · PAN-OS

Using a different authentication method and disabling SAML authentication will completely mitigate the issue. Until an upgrade can be performed, applying both these mitigations (a) and (b) eliminates the configuration required for exposure to this vulnerability: (a) Ensure that the 'Identity Provider Certificate' is configured. Configuring the 'Identity Provider Certificate' is an essential part of a secure SAML authentication configuration. (b) If the identity provider (IdP) certificate is a certificate authority (CA) signed certificate, then ensure that the 'Validate Identity Provider Certificate' option is enabled in the SAML Identity Provider Server Profile. Many popular IdPs generate self-signed IdP certificates by default and the 'Validate Identity Provider Certificate' option cannot be enabled. Additional steps may be required to use a certificate signed by a CA. This certificate…

Vendor remediation · PAN-OS

This issue is fixed in PAN-OS 8.1.15, PAN-OS 9.0.9, PAN-OS 9.1.3, and all later versions. Important: Ensure that the signing certificate for your SAML Identity Provider is configured as the 'Identity Provider Certificate' before you upgrade to a fixed version to ensure that your users can continue to authenticate successfully. Configuring the 'Identity Provider Certificate' is an essential part of a secure SAML authentication configuration. https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/authentication/configure-saml-authentication Details of all actions required before and after upgrading PAN-OS are available in https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA14u0000008UXK. To eliminate unauthorized sessions on GlobalProtect portals and gateways, Prisma Access managed through Panorama, change the certificate used to encrypt and decrypt the Authentication Over…

References

Provenance

Every fact on this page comes from the sources below. Nothing is written by an AI.

Palo Alto Networks (CVE record)
Palo Alto Networks (CVE record) · 27 Sept 2026, 23:46 UTC · Parser patcharo-cve5/1.1.0
CISA Known Exploited Vulnerabilities
CISA Known Exploited Vulnerabilities · 27 Sept 2026, 23:42 UTC · Parser patcharo-kev/1.0.0
NVD
NVD · 27 Sept 2026, 23:44 UTC · Parser patcharo-nvd/1.0.0
FIRST EPSS
FIRST EPSS · 27 Sept 2026, 23:46 UTC · Parser patcharo-epss/1.0.0

Last verified: 28 Sept 2026, 02:31 UTC