Exploited CVEs / Palo Alto Networks / CVE-2020-2021

CVE-2020-2021

Palo Alto Networks PAN-OS Authentication Bypass Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2022-04-15 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Palo Alto Networks Security Advisories, linked below.

Risk summary

CriticalCISA KEVRansomware

10.0

CVSS v3 base

4.4%

EPSS exploit probability

Critical

Severity

2022-03-25

Added to KEV

2022-04-15 (past due)

CISA due date

Actively exploited Palo Alto Networks PAN-OS vulnerability, Critical severity, CVSS v3 10.0. Added to the CISA KEV catalog 2022-03-25.

Senserva AI read on CVE-2020-2021 CISA required action Official fix for CVE-2020-2021 Admin questions

Senserva AI Opinion for CVE-2020-2021

When SAML authentication is in use, this Palo Alto Networks PAN-OS flaw lets attackers bypass authentication entirely, a perfect 10.0 CVSS with confirmed ransomware use. An identity check failing open on a firewall or VPN gateway is an identity-layer catastrophe rather than a routine software bug. Its low 4 percent EPSS reflects the specific SAML precondition, not low impact.

Do this: Verify PAN-OS devices using SAML are patched for CVE-2020-2021 and review authentication logs from any period spent unpatched.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2020-2021

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2020-2021, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2020-2021.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed once a day (early morning US Central)):
- CVE-2020-2021: Palo Alto Networks PAN-OS Authentication Bypass Vulnerability
- Affected: Palo Alto Networks PAN-OS
- Severity: Critical, CVSS v3 10.0; EPSS 30-day exploitation probability 4.4%
- Added to CISA KEV: 2022-03-25; federal remediation due 2022-04-15
- Ransomware-linked: YES
- CISA required action: Apply updates per vendor instructions.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch immediately

Exploited in the wild and used in ransomware campaigns.

The fix ships from the vendor: Palo Alto Networks Security Advisories.

Do this now: Move this ahead of everything else in the queue, then verify the fix actually landed on every exposed device.

Updated September 3, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2020-2021

Published: 2022-03-25
Last revised: 2022-03-25
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2022-03-25 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 10.0; EPSS first scored at 4.4%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2022-04-15 (past due).

Apply updates per vendor instructions.

Official fix for CVE-2020-2021

The authoritative fix and affected-version list are published by the vendor. Find the PAN-OS advisory on Palo Alto Networks Security Advisories.

Palo Alto Networks Security Advisories CISA KEV entry

Common questions about CVE-2020-2021

Is CVE-2020-2021 actively exploited?

Yes. CVE-2020-2021 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2022-03-25, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 4.4%. CISA also reports it is known to be used in ransomware campaigns.

What is the CISA deadline and required action for CVE-2020-2021?

CISA set the federal (BOD 22-01) remediation due date at 2022-04-15, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.

What fixes CVE-2020-2021?

The authoritative fix is in the vendor advisory: see Palo Alto Networks Security Advisories for the patched PAN-OS versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2020-2021?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2020-2021's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed once a day (early morning US Central).

Scope and sources

More exploited Palo Alto Networks CVEs: CVE-2026-0257 CVE-2026-0300 CVE-2025-0111 CVE-2025-0108 CVE-2024-3393 CVE-2024-0012 CVE-2024-9474 CVE-2024-9465
All Palo Alto Networks exploited CVEs on one page: Palo Alto Networks vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.