{"id":"CVE-2020-2021","published":"2020-06-29T15:15:12Z","modified":"2026-06-17T03:11:38Z","title":"Palo Alto Networks PAN-OS Authentication Bypass Vulnerability","vendor":"Palo Alto Networks","product":"PAN-OS","tier":"core","eol":null,"description":{"text":"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.","provenance":"source","from":"NVD"},"summary":{"text":"PAN-OS, Palo Alto Networks' firewall and VPN operating system, improperly verifies signatures in its SAML authentication when the \"Validate Identity Provider Certificate\" option is disabled, affecting the GlobalProtect, Captive Portal, Clientless VPN, and web interface components across the listed 9.x and 8.x releases. An unauthenticated attacker with network access to the affected server can gain access to protected resources, or log in as an administrator to the PAN-OS or Panorama web interfaces, provided SAML is in use and that certificate validation setting is off.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-23T07:04:29Z"},"cvss":{"score":10.0,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.04362,"percentile":0.91226,"date":"2026-10-29","provenance":"source"},"kev":{"dateAdded":"2022-03-25","dueDate":"2022-04-15","ransomware":true,"requiredAction":"Apply updates per vendor instructions.","notes":"https://nvd.nist.gov/vuln/detail/CVE-2020-2021","provenance":"source"},"vulncheckKev":{"dateAdded":"2020-09-17","exploitedFirstSeen":"2020-09-17","ransomware":true,"evidence":[{"url":"https://www.esentire.com/security-advisories/ransomware-groups-exploit-remote-access-services","date":"2020-09-17"},{"url":"https://cisa.gov/news-events/cybersecurity-advisories/aa20-283a","date":"2020-10-24"},{"url":"https://github.com/blackorbird/APT_REPORT/raw/master/summary/2021/The%20CrowdStrike%202021%20Global%20Threat%20Report.pdf","date":"2021-04-02"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2022-03-25"},{"url":"https://static.tenable.com/marketing/whitepapers/Whitepaper-Ransomware_Ecosystem.pdf","date":"2022-06-22"},{"url":"https://cert-in.org.in/PDF/RANSOMWARE_Report_2022.pdf","date":"2023-04-22"}],"evidenceTotal":6,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"},{"name":"Actively_Exploited_Kev | Oct 22, 2026","url":"https://otx.alienvault.com/pulse/6ad8d33a077cbb5cab524d80","created":"2026-10-21"},{"name":"Actively_Exploited_Kev | Oct 21, 2026","url":"https://otx.alienvault.com/pulse/6ad78130c4d1ac2be83a8b6d","created":"2026-10-20"},{"name":"Actively_Exploited_Kev | Oct 20, 2026","url":"https://otx.alienvault.com/pulse/6ad62f63c24a405a3423cc13","created":"2026-10-19"},{"name":"Actively_Exploited_Kev | Oct 19, 2026","url":"https://otx.alienvault.com/pulse/6ad4dda174e5797d0bd238b7","created":"2026-10-18"},{"name":"Actively_Exploited_Kev | Oct 18, 2026","url":"https://otx.alienvault.com/pulse/6ad38c22e1848f8189d1c121","created":"2026-10-17"}],"provenance":"machine"},"cwes":[{"id":"CWE-347","name":"Improper Verification of Cryptographic Signature"}],"references":[{"url":"https://security.paloaltonetworks.com/CVE-2020-2021","tags":["Mitigation","Vendor Advisory"]},{"url":"https://security.paloaltonetworks.com/CVE-2020-2021","tags":["Mitigation","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-2021","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: unauthenticated network attacker exploits public-facing SAML interface","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"an unauthenticated attacker with network access to the affected servers can gain access to protected resources","start":1265,"end":1375}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1078","name":"Valid Accounts","tactics":["initial-access","persistence","privilege-escalation","stealth"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: gains valid access via bypassed SAML authentication","mappingType":"primary_impact","evidence":[{"from":"description","quote":"enables an unauthenticated network-based attacker to access protected resources","start":220,"end":299}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2020-22049","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2020-22049","exploited":true,"exploitedSince":"2022-03-25","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":0,"earliest":"2026-09-05","earliestUrl":"https://github.com/mngunibanda1-prog/Jozini-network-scanner","repos":[{"name":"mngunibanda1-prog/Jozini-network-scanner","url":"https://github.com/mngunibanda1-prog/Jozini-network-scanner","stars":0,"created":"2026-09-05"}]},"first":{"date":"2026-09-05","source":"PoC-in-GitHub","url":"https://github.com/mngunibanda1-prog/Jozini-network-scanner"},"provenance":"source"},"exploitRefs":[],"flow":[{"stage":"exploitation","techniques":["T1190"],"provenance":"ai"},{"stage":"primary","techniques":["T1078"],"provenance":"ai"}],"timeline":[{"date":"2020-06-29","kind":"published","label":"Published 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