CVE-2020-2021

When Security Assertion Markup Language (SAML) authentication is enabled and the 'Validate Identity Provider Certificate' option is disabled…

Browse: All 2020 CVEs · All vendors

CVSS score
10.0 Critical
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA KEV
Yes — actively exploited (added 2022-03-25, remediation due 2022-04-15)
Ransomware
Known ransomware campaign use
Weakness (CWE)
CWE-347
Published
2020-06-29
Last modified
2026-06-17
NVD status
Analyzed

Description

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 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:H). If the web interfaces are only accessible to a restricted management network, then the issue is lowered to a CVSS Base Score of 9.6 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H). Palo Alto Networks is not aware of any malicious attempts to exploit this vulnerability.

Affected products

Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.

Required action (CISA)

Apply updates per vendor instructions. Federal remediation deadline: 2022-04-15.

How to prioritize this

This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score. For the actively exploited vulnerabilities that matter this week, read The Exploit HQ daily security brief.

References

FAQ

Is CVE-2020-2021 actively exploited?

Yes. CISA added CVE-2020-2021 to its Known Exploited Vulnerabilities (KEV) catalog on 2022-03-25, with a federal remediation deadline of 2022-04-15. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.

What is the CVSS score of CVE-2020-2021?

CVE-2020-2021 has a CVSS base score of 10.0 (Critical). Its vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Related vulnerabilities

Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.