Security readout for executives and security teams
Plain-English summary
Some Juniper SRX firewalls running affected Junos OS tenant services may let a tenant administrator affect traffic handling beyond their own tenant. In multi-tenant deployments, this can expose one tenant’s traffic to another tenant or disrupt shared device traffic management.
Executive priority
Prioritize for managed security or service-provider environments where multiple customers share SRX tenant services. The business risk is tenant isolation failure, not broad internet compromise.
Technical view
CVE-2021-0246 is an incorrect default permissions issue in Junos OS tenant services on specified SRX platforms with SPC2 or SPC3. A high-privileged local tenant system administrator may alter device-wide traffic management or cause traffic leakage across tenants. CVSS is 7.3 with changed scope.
Likely exposure
Exposure appears limited to multi-tenant Juniper SRX1500, SRX4100, SRX4200, SRX4600, and SRX5000 Series deployments using tenant services on affected Junos OS releases and SPC2/SPC3 combinations.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. The attack requires local access and high privileges as a tenant system administrator, but impact crosses tenant boundaries and can affect the service provider.
Researcher notes
Evidence supports a permission design flaw with local, high-privilege preconditions and cross-tenant impact. The bundle names affected release ranges but does not include exploit details, proof of active exploitation, or full vendor workaround text.
Mitigation direction
- Inventory SRX tenant-service deployments and identify SPC2/SPC3 hardware.
- Compare Junos OS releases against Juniper advisory JSA11139.
- Upgrade or remediate according to Juniper’s vendor guidance.
- Restrict tenant administrator access to trusted users until remediation is complete.
- Review tenant isolation assumptions for affected shared-firewall services.
Validation and detection
- Confirm whether tenant services are enabled on listed SRX platforms.
- Record Junos OS version and hardware module type for each device.
- Check for affected 18.3, 18.4, and 19.1 release levels.
- Review configuration permissions granted to tenant system administrators.
- Look for unexpected tenant-to-tenant traffic handling or routing anomalies.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-276: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-0246 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:H/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:H/A:L1.55.3Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.juniper.net/JSA11139CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Incorrect Default Permissions
Incorrect Default Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.