CVE-2020-2021General(paloaltonetworks / pan-os)

LOWCVSS 10.0 · CRITICALCISA KEV

Exploitation ongoing with high activity in latest observed window (1 mentions)

Immediate actions

  • Prioritize remediation for paloaltonetworks pan-os systems immediately
  • Assume compromise if assets are exposed
  • Track advisory updates for patch or workaround availability

Recommended action window: Immediate (within 24h)

NVD 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.

3.5/ 10 priority

Sources & remediation

Listed in the CISA Known Exploited Vulnerabilities catalog. Federal remediation due date: 2022-04-15. Apply updates per vendor instructions.

Weakness type (CWE)
CWE-347

Priority

LOW

Exploitation

ACTIVE

PoC

NONE

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • pan-os

Threat summary

  • Active exploitation appears in 1 classified signals
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Active exploitation reported across 1 signal
  • Technical details provided in 1 signal
  • General: 1 classified signal
  • Peaked 1d ago at 1 mentions (2026-05-21); latest day: 1
  • 2 total mentions across 2 days

Affected systems

Products
pan-os

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-05-21: 1Mentions · 2026-06-17: 1Active Exploitation · 2026-06-17: 1Technical Details · 2026-06-17: 105-2106-17
Signal classification2 categories
General
150.0%
Active Exploitation
150.0%
Referenced assets1 URL
Classification over time
DateTotalLabels
2026-05-211
General1
2026-06-171
Active Exploitation1
Full discourse2 posts
  • Nathan McNulty@NathanMcNulty
    General

    CVE-2020-2033, CVE-2020-2021, CVE-2020-2050, CVE-2026-0257, and now CVE-2026-0265 Authentication bypass, as in direct access to your internal networks over the Internet This VPN architecture should be dead, get it off the Internet, it's a time bomb waiting to happen

    Post summary

    The message lists several CVEs and warns of authentication bypass in VPNs, but offers no concrete technical details, exploit code, or mitigation information.

    4596452212113.6K
    18.5K followersView on X
  • ThreatCluster@threatcluster
    Active Exploitation

    CISA said it has added Microsoft Exchange RCE flaws CVE-2020-16875 and CVE-2020-17132 and PAN-OS SAML auth bug CVE-2020-2021 to its Known Exploited Vulnerabilities list after detecting active exploitation. https://threatcluster.io/cluster/critical-microsoft-exchange-vulnerabilities-exploited-in-the-7eaea81b

    Post summary

    CISA has added three CVEs to its Known Exploited Vulnerabilities list after confirming active exploitation in the wild, indicating these vulnerabilities are currently being abused by attackers.

    0001068
    356 followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
OSpaloaltonetworkspan-os---

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