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Steel Belted Radius CarrierApplication · Juniper

CVE-2021-0276

CRITICAL · 9.8 CVSS v3.1 Published 2021-07-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A stack-based Buffer Overflow vulnerability in Juniper Networks SBR Carrier with EAP (Extensible Authentication Protocol) authentication configured, allows an attacker sending specific packets causing the radius daemon to crash resulting with a Denial of Service (DoS) or leading to remote code execution (RCE). By continuously sending this specific packets, an attacker can repeatedly crash the radius daemon, causing a sustained Denial of Service (DoS). This issue affects Juniper Networks SBR Carrier: 8.4.1 versions prior to 8.4.1R19; 8.5.0 versions prior to 8.5.0R10; 8.6.0 versions prior to 8.6.0R4.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A stack-based buffer overflow vulnerability in Juniper SBR Carrier's radius daemon exists when EAP (Extensible Authentication Protocol) is configured. An unauthenticated attacker can send specially crafted packets to trigger the overflow, causing denial of service or potentially achieving remote code execution. The vulnerability allows sustained DoS via repeated crashes of the radius daemon.

MitigationApply the vendor-supplied patches: upgrade to 8.4.1R19, 8.5.0R10, or 8.6.0R4 or later. If immediate patching is not possible, consider disabling EAP authentication or restricting network access to the RADIUS service.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Steel Belted Radius CarrierApplication
Affected:= 8.4.1= 8.5.0= 8.6.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Juniper SBR Carrier installation
    Locate the Steel Belted Radius Carrier installation directory or check installed software packages on the system
    Affected if Juniper Steel Belted Radius Carrier is not present on the system
  2. Verify the SBR Carrier version
    Check the installed version of Steel Belted Radius Carrier against the affected versions: 8.4.1, 8.5.0, or 8.6.0
    Affected if The installed version matches exactly 8.4.1, 8.5.0, or 8.6.0
  3. Confirm EAP authentication is enabled
    Inspect the RADIUS server configuration to determine whether Extensible Authentication Protocol (EAP) is configured as an authentication method
    Affected if EAP authentication is enabled in the RADIUS configuration
  4. Assess network exposure of RADIUS service
    Verify whether the RADIUS daemon port (typically UDP 1812) is accessible from untrusted networks
    Affected if The RADIUS service is exposed to untrusted or public networks

A user is affected if they have Steel Belted Radius Carrier version 8.4.1, 8.5.0, or 8.6.0 with EAP authentication enabled and the RADIUS service is network-accessible.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-supplied patches: upgrade to 8.4.1R19, 8.5.0R10, or 8.6.0R4 or later. If immediate patching is not possible, consider disabling EAP authentication or restricting network access to the RADIUS service.

Recommended fix High confidence

Upgrade to 8.4.1R19 (if on 8.4.1), 8.5.0R10 (if on 8.5.0), or 8.6.0R4 (if on 8.6.0) - choose the next sequential release for your current branch

  1. 1. Identify the currently installed SBR Carrier version by checking the system or running: 'sbrc -version' or reviewing system documentation
  2. 2. Determine which upgrade path applies based on current version (8.4.1 -> 8.4.1R19, 8.5.0 -> 8.5.0R10, or 8.6.0 -> 8.6.0R4)
  3. 3. Download the appropriate fixed release from the Juniper Networks download portal or contact Juniper support
  4. 4. Review the release notes for the target version (8.4.1R19, 8.5.0R10, or 8.6.0R4) for any specific upgrade prerequisites or注意事项
  5. 5. Back up the current SBR Carrier configuration before proceeding with the upgrade
  6. 6. Install the upgrade following Juniper's standard upgrade procedure for SBR Carrier
  7. 7. After upgrade, verify the radius daemon is running: 'radcheck' or similar status command
  8. 8. Confirm the fixed version is installed: 'sbrc -version'
Caveat Review release notes for your specific version transition; upgrade within same major.minor branch is typically low-risk but verify release notes for any configuration or behavioral changes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Steel Belted Radius Carrier Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-0276 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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