Security readout for executives and security teams
Plain-English summary
A user with local low-level access to affected Juniper NFX Series devices could abuse the Junos Device Management Daemon to gain higher privileges. This is not described as remote exploitation, but compromise of an account on these devices could become full device compromise.
Executive priority
Treat as high priority for affected NFX infrastructure, especially shared or service-provider environments. The vulnerability is local, but a single compromised low-privileged device account could become a path to full control of the appliance.
Technical view
CVE-2021-0252 is a Junos OS NFX Series local code execution issue in JDMD, mapped to CWE-77. CVSS 3.1 is 7.8 with local attack vector, low complexity, low privileges required, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to Juniper Networks Junos OS on NFX Series in the listed 18.1 through 19.2 release ranges. Sources say versions before 18.1R1 and JDMD use in Junos Node Slicing on specified MX platforms are not affected.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. The attack requires local low-privileged access, so risk is highest where many operators, tenants, automation accounts, or compromised credentials can access NFX devices.
Researcher notes
Evidence supports local privilege escalation via JDMD on NFX Series only. The source bundle does not provide exploit code, active exploitation evidence, or detailed root-cause mechanics beyond CWE-77 and Juniper’s affected-version matrix.
Mitigation direction
- Upgrade affected NFX devices to Juniper fixed releases listed in JSA11145.
- Prioritize devices running 18.1 through 19.2 affected release trains.
- Review and reduce local user access on NFX devices.
- Check Juniper JSA11145 for current vendor guidance before maintenance.
- Monitor privileged access paths and administrative account use.
Validation and detection
- Inventory all Juniper NFX Series devices and their Junos OS versions.
- Compare running versions against the affected ranges in CVE-2021-0252.
- Confirm non-NFX and stated MX Node Slicing deployments are not misclassified.
- Review local accounts, automation users, and recent privilege changes.
- Verify remediation by confirming the installed Junos fixed release.
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
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-0252 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.juniper.net/JSA11145CVE reference · x_refsource_MISC
- https://github.com/orangecertcc/security-research/security/advisories/GHSA-gr7j-26pv-5v57CVE 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.
Improper Neutralization of Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.