CASCACascade Atlas

Evidence dossier

CVE-2020-2021

PAN-OS: Authentication Bypass in SAML Authentication

Exploited in the wild (CISA KEV since Mar 25, 2022). NVD reports CVSS 3.1 10.0. EPSS estimates 4.4% exploit likelihood as of Aug 27, 2026.

71.8–73.4Priority evidence range
Evidence current through Aug 27, 2026, 6:09 PM UTC

As of Aug 27, 2026

Normalized restatement

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.

State
PUBLISHED
Published
Jun 29, 2020
Updated
Oct 21, 2025
Evidence coverage
97%

Evidence chronology

What was known when

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  1. Source dateSource date omittedFirst observed by CASCA
    CISA-ADP

    Record text: CISA ADP Vulnrichment

    Inspect raw assertion
    Field
    container
    Value
    CISA ADP Vulnrichment
    Original evidence ↗
  2. Source dateSource date omittedFirst observed by CASCA
    CVE Program

    Record text: CVE Program Container

    Inspect raw assertion
    Field
    container
    Value
    CVE Program Container
    Original evidence ↗
  3. Source dateSource date omittedFirst observed by CASCA
    palo_alto

    Record text: PAN-OS: Authentication Bypass in SAML Authentication

    Inspect raw assertion
    Field
    container
    Value
    PAN-OS: Authentication Bypass in SAML Authentication
    Original evidence ↗
  4. Source dateFirst observed by CASCA
    CISA KEV

    Exploitation cataloged: Palo Alto Networks PAN-OS Authentication Bypass Vulnerability

    Inspect raw assertion
    Field
    observed_exploitation
    Value
    Palo Alto Networks PAN-OS Authentication Bypass Vulnerability
    Original evidence ↗
  5. Source dateFirst observed by CASCA
    FIRST EPSS

    EPSS score: 4.36% probability · 90.54th percentile

    Inspect raw assertion
    Field
    model_probability
    Value
    Probability 0.043620000000; percentile 0.905350000000
    Original evidence ↗
ExploitationCatalog member

CISA KEV · catalog date Mar 25, 2022 · first observed Jul 19, 2026

Exploit likelihood4.36%

FIRST EPSS · score date Aug 27, 2026 · 90.5th percentile · first observed Aug 27, 2026

SeverityCVSS 10.0

NVD · CVSS 3.1 · first observed Jul 19, 2026 · same-version scores align in this snapshot

Evidence detail

Source limits and decisions

Why each evidence state has this value

casca-unknown-reasons-v1
Exploitation statusEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Exploit likelihoodEvidence supported

Eligible evidence is present for this bounded claim.

Revision
evidence-policy-v1.1.0
Cutoff
Aug 27, 2026
Resolution
None
Severity assessmentEvidence supported

Eligible evidence is present for this bounded claim.

Revision
casca-direct-cvss-eligibility-v1
Cutoff
Aug 27, 2026
Resolution
None
Affected productsSource-reported scope

The cited source assertion is retained while canonical product linkage remains open.

Revision
casca-factor-d-obligations-v1
Cutoff
Aug 27, 2026
Resolution
Resolve identity

Source comparison

Who said what

CISA-ADPIndependent enrichment
Record text

CISA ADP Vulnrichment

Inspect raw assertion
Field
container
Value
CISA ADP Vulnrichment
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CVE ProgramDerivative copy
Record text

CVE Program Container

Inspect raw assertion
Field
container
Value
CVE Program Container
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
palo_altoOriginal assertion
Record text

PAN-OS: Authentication Bypass in SAML Authentication

Inspect raw assertion
Field
container
Value
PAN-OS: Authentication Bypass in SAML Authentication
Source dateSource date omittedFirst observed by CASCAOriginal evidence ↗
CISA KEVOriginal assertion
Exploitation cataloged

Palo Alto Networks PAN-OS Authentication Bypass Vulnerability

Inspect raw assertion
Field
observed_exploitation
Value
Palo Alto Networks PAN-OS Authentication Bypass Vulnerability
Source dateFirst observed by CASCAOriginal evidence ↗
FIRST EPSSOriginal assertion
EPSS score

4.36% probability · 90.54th percentile

Inspect raw assertion
Field
model_probability
Value
Probability 0.043620000000; percentile 0.905350000000
Source dateFirst observed by CASCAOriginal evidence ↗

Applicability

Cited product scope

Trace impact →
4Underlying assertions
1Canonical products
4Target assertions
0Constraint assertions

Grouped from 1 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.

Identity source boundaries
  • Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z27d65b0f-b718-4b4f-bb79-c47c68d09dfa
  • Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z955dae73-7302-438b-aee1-058d7cc5d48e

2 scope groups

palo_alto · source assertedPalo Alto NetworksPAN-OSDirect source scope
Unaffected: 7.1.*Affected: 8.0.*Affected: 8.1 to before 8.1.15 (custom comparison)Affected: 9.0 to before 9.0.9 (custom comparison)Affected: 9.1 to before 9.1.3 (custom comparison)
Source-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Inspect raw assertion[{"status": "unaffected", "version": "7.1.*"}, {"status": "affected", "version": "8.0.*"}, {"status": "affected", "version": "8.1", "lessThan": "8.1.15", "versionType": "custom"}, {"status": "affected", "version": "9.0", "lessThan": "9.0.9", "versionType": "custom"}, {"status": "affected", "version": "9.1", "lessThan": "9.1.3", "versionType": "custom"}]
NVD CPE · OPERATING SYSTEMpaloaltonetworkspan-osVulnerable target · 4 assertions
Any version (unconstrained) (>= 8.0.0, <= 8.0.20); Any version (unconstrained) (>= 8.1.0, < 8.1.15); Any version (unconstrained) (>= 9.0.0, < 9.0.9); Any version (unconstrained) (>= 9.1.0, < 9.1.3)Canonical identity product-612afb736440531327cd224402d663e14e2a3f421cc65267d8acade0f3b99df7Linked exact
Scope supported
Inspect raw assertions
  1. cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 3
    Logic
    OR
    Version bounds
    from including 9.1.0; through excluding 9.1.3
    Match ID
    4e9f14e9-3cd7-443b-9d97-254e917fa22b
  2. cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 0
    Logic
    OR
    Version bounds
    from including 8.0.0; through including 8.0.20
    Match ID
    2befbf38-af84-4477-a6b9-5bdd51d54f4f
  3. cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 1
    Logic
    OR
    Version bounds
    from including 8.1.0; through excluding 8.1.15
    Match ID
    6116c706-6ac7-476d-9624-c0d4be3d497a
  4. cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
    Official link
    Linked exact
    Role
    Vulnerable target
    Configuration
    0 · node/0 · match 2
    Logic
    OR
    Version bounds
    from including 9.0.0; through excluding 9.0.9
    Match ID
    6d6e8b99-4150-4ae8-a580-08ac71f64760

Affected-product evidence

Accepted scope and product mapping

1 canonical links · 1 source-reported links

Mapping establishedEvidence supported

vendor-14ea140e990b8248b82877833fdf14fba1a48c6d230b7a5c9157d2a4ac9f719b · product-612afb736440531327cd224402d663e14e2a3f421cc65267d8acade0f3b99df7

Source class
Nvd cpe vulnerable target
Assertions
4
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
30dc0c79-27de-427d-9cdb-b0a415d80863e45f945d-3ec6-4257-879a-91bb928530d0eb538d88-6f7e-4bf4-8feb-71b39b377519fc735fab-3429-49a3-a0e5-b423d1c57890
Source-reported scopeSource-reported scope

Canonical linkage remains open; the cited source assertion is retained below.

Vendor specified only by source · Product specified only by source

Source class
Direct cve affected
Assertions
1
Mapping revision
cpe23-exact-mapping-v1
Observed cutoff
Aug 27, 2026
Retained assertion IDs
926d0764-804c-408b-9dfc-9c8761176f37

Assessments

CVSS by origin

10.0
NVDCVSS 3.1 · role Primary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
9.3
NVDCVSS 2.0 · role Primary · priority eligiblevalid_matchAV:N/AC:M/Au:N/C:C/I:C/A:C
10.0
psirt@paloaltonetworks.comCVSS 3.1 · role Secondary · priority eligiblevalid_matchCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
10.0
palo_altoCVSS 3.1 · role unknown · display onlyDirect record assessment retained outside normalized eligibilityCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Direct CVE/CNA normalized decisions

10.0Priority eligible

palo_alto

CVSS 3.1 · Primary · Original assertion · rank 1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Validation
Valid match
Recomputed
10.0
Decision reason
Evidence supported
Policy
casca-direct-cvss-eligibility-v1

Assessments are retained side by side under closed precedence. Cascade never averages CVSS.

Evidence boundaries

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; remaining scope stays source-scoped.
  • NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
  • OSV aggregation and OSV-converted NVD material are not independent corroboration.
  • Red Hat facts are vendor assertions for the exact supplied products.
  • Nonmembership and not-yet-observed states are not proof of safety.