Security readout for executives and security teams
Plain-English summary
CVE-2021-0248 is a critical Juniper NFX Series issue where hard-coded credentials in Junos OS could let an unauthenticated attacker take over an NFX deployment through administrative interfaces. It affects NFX Series running Junos OS before 19.1R1. The bundle says NFX NextGen and non-NFX platforms are not affected.
Executive priority
Treat this as urgent for any organization operating Juniper NFX Series. A vulnerable, reachable administrative interface could allow full takeover without credentials. Prioritize asset identification, management-interface isolation, and upgrade validation.
Technical view
The flaw is CWE-798 hard-coded credentials in Junos OS for NFX Series. CVSS 3.1 is 10.0, indicating network-reachable, low-complexity, no-auth compromise with complete confidentiality, integrity, and availability impact, but only via administrative interfaces.
Likely exposure
Exposure is limited to Juniper NFX Series devices running Junos OS earlier than 19.1R1, especially where administrative interfaces are reachable from untrusted networks. NFX NextGen Software and other Juniper platforms are stated as not affected.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The risk remains severe because the vulnerability uses hard-coded credentials, requires no prior authentication, and targets administrative interfaces that control the deployment.
Researcher notes
The provided evidence identifies product scope, affected version boundary, CWE-798, and CVSS 10.0. It does not provide exploit details, observed exploitation, or broader platform impact. Avoid expanding scope beyond NFX Series Junos OS before 19.1R1.
Mitigation direction
- Inventory Juniper NFX Series devices and record Junos OS versions.
- Upgrade affected NFX Series Junos OS deployments to 19.1R1 or later.
- Restrict administrative interfaces to trusted management networks only.
- Review Juniper JSA11141 for current vendor guidance and fixed-release details.
- Remove internet exposure for administrative interfaces wherever possible.
Validation and detection
- Confirm whether each device is NFX Series, not NFX NextGen Software.
- Verify Junos OS version is 19.1R1 or later on NFX Series.
- Check administrative interfaces are not reachable from untrusted networks.
- Review access logs for unexpected administrative access attempts.
- Document non-NFX platforms as out of scope based on vendor scope.
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-798: Credential and account abuse lookup
Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. 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 lookupCVE-2021-0248 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
- Critical
- CVSS
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.juniper.net/JSA11141CVE 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.
Use of Hard-coded Credentials
Use of Hard-coded Credentials represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.