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.
CVE-2020-2021
“—” beside the score: it is equal to NVD's CVSS score.
Score elevated to 10.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 10.0 retained for reference. Confidence: HIGH.
Also known asEUVD-2020-22049 (ENISA EUVD) · GHSA-84wc-9427-hw23 (GitHub Security Advisories)Source: ENISA EUVD
- Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low mission impact
A fix is available — apply it.
Fixed versions, as the CVE record's CNA (Palo Alto Networks, Inc.) states them: "This issue is fixed in PAN-OS 8.1.15, PAN-OS 9.0.9, PAN-OS 9.1.3, and all later versions."
- CVSS v3
- 10.0
- EG Score
- 10.0CRITICALhigh confidence
- EG Risk
- 100EG Risk 100/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity100% × 45%Impact severity (EG Severity): CVSS 10.0 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation100% × 40%Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Attend at low mission impact; Act at medium or high.Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it sooner than your standard update timelines at low mission impact and as soon as possible at medium or high. - EPSS PROB
- 4.4%
- EPSS %ILE
- 91st
- KEV
- ⚠ Exploited
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (10.0): severity, escalated by confirmed exploitation. This CVE's 10.0 is its impact severity (EG Severity), not escalated.
- EG Severity
- 10.0 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 4.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- CISA KEV and EG-KEV Tier 1 (exploited in the wild)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Act at medium mission impactAttend at low mission impact; Act at medium or high.CISA BOD 26-04: 3 days & forensic triage if the affected system is publicly exposed; 3 days & forensic triage if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Attend at low mission impact; Act at medium or high.
A fix is available. Apply it sooner than your standard update timelines at low mission impact and as soon as possible at medium or high.
Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)3 days & forensic triage if the affected system is publicly exposed; 3 days & forensic triage if it is not.
The score's inputs: In CISA KEV yes (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
CISA required action“Apply updates per vendor instructions.”
Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://nvd.nist.gov/vuln/detail/CVE-2020-2021
Published
June 29, 2020
Last Modified
November 4, 2025
Advisory Details (2)
Auto-updated Nov 1, 2026Known Exploited Vulnerabilities Catalog | CISA
Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-2021CVE-2020-2021 PAN-OS: Authentication Bypass in SAML Authentication
https://security.paloaltonetworks.com/CVE-2020-2021Vendor Advisories for CVE-2020-2021(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 21× in last 7d / 127× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 1,095 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 995 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 16:36 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-11-02 06:18 UTCEG score recompute
- 2026-11-02 06:18 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-11-01 16:29 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-11-01 05:16 UTCEG score recompute
- 2026-11-01 05:16 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-31 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-31 04:13 UTCEG score recompute
- 2026-10-31 04:13 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-30 16:29 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-30 03:07 UTCEG score recompute
- 2026-10-30 03:07 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-29 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-29 02:05 UTCEG score recompute
- 2026-10-29 02:05 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-28 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-28 01:00 UTCEG score recompute
- 2026-10-28 00:59 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-27 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-26 23:56 UTCEG score recompute
- 2026-10-26 23:55 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-26 16:27 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-25 22:52 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-25 18:48 UTCEG score recompute
- 2026-10-25 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
Show 75 moreShow fewer
- 2026-10-24 21:49 UTCEG score recompute
- 2026-10-24 21:49 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-24 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-23 20:47 UTCEG score recompute
- 2026-10-23 20:47 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-22 19:45 UTCEG score recompute
- 2026-10-22 19:44 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-21 18:42 UTCEG score recompute
- 2026-10-21 18:42 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-20 17:39 UTCEG score recompute
- 2026-10-20 17:39 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-19 16:37 UTCEG score recompute
- 2026-10-19 16:37 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-19 16:27 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-18 15:32 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-18 09:30 UTCEG score recompute
- 2026-10-17 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-17 14:30 UTCEG score recompute
- 2026-10-17 14:30 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-16 16:33 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-16 13:27 UTCEG score recompute
- 2026-10-16 13:27 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-15 16:27 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-15 12:25 UTCEG score recompute
- 2026-10-15 12:25 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-14 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-14 11:23 UTCEG score recompute
- 2026-10-14 11:22 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-13 16:28 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-13 10:17 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-12 19:42 UTCEG score recompute
- 2026-10-12 16:29 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-12 09:13 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-12 04:57 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-12 00:41 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-11 20:26 UTCEG score recompute
- 2026-10-11 20:26 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-11 16:10 UTCEG score recompute
- 2026-10-11 16:10 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-11 13:43 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-11 11:55 UTCEG score recompute
- 2026-10-11 11:55 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-11 07:37 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-11 03:22 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 23:05 UTCEG score recompute
- 2026-10-10 23:05 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-10 18:49 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 14:34 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 10:18 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 06:03 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-10 01:49 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 21:34 UTCEG score recompute
- 2026-10-09 21:34 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 4.4% · 91st percentile
- 2026-10-09 17:19 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 13:02 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 08:47 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 04:31 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-09 00:16 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-08 20:01 UTCEG score recompute
- 2026-10-08 20:01 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-08 16:38 UTCEPSS rescoreEPSS 4.4% · 90th percentile
- 2026-10-08 15:43 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-08 11:27 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-08 07:12 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-08 02:56 UTCEG score recompute
- 2026-10-08 02:56 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
- 2026-10-07 23:44 UTCEPSS rescoreEPSS 4.4% · 90th percentile
- 2026-10-07 22:41 UTCGHSA enrichmentGHSA-84wc-9427-hw23 · GitHub severity HIGH · GitHub CVSS 10.0
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Frequently asked(6)
What is CVE-2020-2021?
When was CVE-2020-2021 made public?
Is CVE-2020-2021 actively exploited?
What is the CVSS score of CVE-2020-2021?
Which products are affected by CVE-2020-2021?
How do I remediate CVE-2020-2021?
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