# CVE-2020-2021: Palo Alto Networks PAN-OS Authentication Bypass > Unauthenticated attackers can bypass SAML authentication to access protected resources or gain administrative privileges if certificate validation is disabled. - **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`) - **Exploited in the wild:** Yes, since 25 Mar 2022 (CISA KEV), used in ransomware - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** No - **Published:** 29 Jun 2020 - **Updated:** 21 Oct 2025 - **Also known as:** GHSA-84wc-9427-hw23 ## What is CVE-2020-2021? CVE-2020-2021 is a critical authentication bypass vulnerability in Paloaltonetworks Pan-Os, published on 29 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-347 (Improper Verification of Cryptographic Signature) ## Which versions are affected by CVE-2020-2021? It affects 1 product. Products: Paloaltonetworks Pan-Os. ## How do I fix CVE-2020-2021? No fix has been published for CVE-2020-2021 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 15 Apr 2022. ## Is CVE-2020-2021 being exploited? Yes. Attackers have exploited CVE-2020-2021 in the wild since at least 25 Mar 2022, including in ransomware campaigns. Public exploit code: - # Jozini Network Scanner Built in Termux at KwaQondile Library, Jozini KZN Tools: - scanner.py: Port scanner with banner grabbing (20 ports + report saving) - cve_check.py: Maps RouterOS version to known CVEs Finding: MikroTik RouterOS 6.46.8 vulnerable to CVE-2020-2021 (Critical) Author: [Your Name] - Aspiring Pentester (github_poc): https://github.com/mngunibanda1-prog/Jozini-network-scanner ## Other vulnerabilities in Paloaltonetworks Pan-Os - [CVE-2024-3400](https://insights.sbomify.com/CVE-2024-3400/): Palo Alto Networks PAN-OS Command Injection (critical 10.0, exploited in the wild) - [CVE-2017-15944](https://insights.sbomify.com/CVE-2017-15944/): Palo Alto Networks PAN-OS Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2026-0300](https://insights.sbomify.com/CVE-2026-0300/): Palo Alto Networks PAN-OS Out-of-bounds Write (critical 9.3, exploited in the wild) - [CVE-2024-0012](https://insights.sbomify.com/CVE-2024-0012/): Palo Alto Networks PAN-OS Management Interface Authentication Bypass (critical 9.3, exploited in the wild) - [CVE-2026-109618](https://insights.sbomify.com/CVE-2026-109618/): PHP Memory Corruption (critical 9.2, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-2021 and fix it if it is affected. What it is: CVE-2020-2021 is a critical authentication bypass vulnerability in Paloaltonetworks Pan-Os, published on 29 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: Yes. Attackers have exploited CVE-2020-2021 in the wild since at least 25 Mar 2022, including in ransomware campaigns. Affected product: Paloaltonetworks Pan-Os. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2020-2021/ (Markdown: https://insights.sbomify.com/CVE-2020-2021/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-2021 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-2021 - OSV: https://osv.dev/vulnerability/CVE-2020-2021 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-2021/ Summaries are generated and may contain mistakes; the official description above is the record.