CVE-2023-28974
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 · uneditedAn Improper Check for Unusual or Exceptional Conditions vulnerability in the bbe-smgd of Juniper Networks Junos OS allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). In a Broadband Edge / Subscriber Management scenario on MX Series when a specifically malformed ICMP packet addressed to the device is received from a subscriber the bbe-smgd will crash, affecting the subscriber sessions that are connecting, updating, or terminating. Continued receipt of such packets will lead to a sustained DoS condition. When this issue happens the below log can be seen if the traceoptions for the processes smg-service are enabled: BBE_TRACE(TRACE_LEVEL_INFO, "%s: Dropped unsupported ICMP PKT ... This issue affects Juniper Networks Junos OS on MX Series: All versions prior to 19.4R3-S11; 20.2 versions prior to 20.2R3-S7; 20.3 versions prior to 20.3R3-S6; 20.4 versions prior to 20.4R3-S6; 21.1 versions prior to 21.1R3-S4; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3-S3; 21.4 versions prior to 21.4R3-S2; 22.1 versions prior to 22.1R2-S2, 22.1R3; 22.2 versions prior to 22.2R2; 22.3 versions prior to 22.3R1-S2, 22.3R2.
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 confidenceA malformed ICMP packet sent from a subscriber to an MX Series device triggers a crash in the bbe-smgd (Broadband Edge subscriber management daemon) due to an improper check for unusual conditions. This causes immediate denial of service for the affected subscriber and disrupts connecting, updating, or terminating sessions. Repeated receipt sustains the DoS condition.
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< 19.4= 19.4= 20.2= 20.3= 21.1= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the device modelRun 'show chassis hardware' or 'show version' to confirm the device is an MX Series routerAffected if The device is NOT an MX Series device - this vulnerability only affects MX Series
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Check the Junos OS versionRun 'show version' and compare the installed Junos version against the affected list: < 19.4, 19.4, 20.2, 20.3, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3Affected if The installed version matches any of the listed affected versions - note that versions 20.1, 20.4, 22.4, and later are NOT affected
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Verify subscriber management daemon is activeRun 'show system processes' or 'show system processes extensive | match bbe-smgd' to check if the bbe-smgd (Broadband Edge subscriber management daemon) is runningAffected if The bbe-smgd process is active - this is the daemon that crashes when receiving malformed ICMP packets from subscribers
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Check for subscriber-facing interfacesRun 'show interfaces' and review configuration for subscriber-enabled logical interfaces (e.g., demux interfaces, PPPoE, IPoe, etc.) under the [edit interfaces] hierarchyAffected if Subscriber-facing interfaces exist - these are the vectors through which a malformed ICMP packet could be received to trigger the flaw
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Review crash logs for bbe-smgd eventsRun 'show log messages' and search for recent bbe-smgd crash events, or run 'request support information' and search for 'bbe-smgd' related crashesAffected if Recent crashes of bbe-smgd are logged following malformed ICMP traffic patterns
You are affected if you run an MX Series device with a Junos version matching the affected list AND have subscriber-facing interfaces with bbe-smgd active, as malformed ICMP packets from subscribers will trigger the daemon crash.
Generated from the published advisory. Verify against your own configuration.
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 · scoped19.4
Apply the appropriate Junos OS software update for your version as specified in the Juniper advisory; if patching is not immediately feasible, consider filtering or rate-limiting malformed ICMP traffic from subscriber-facing interfaces at adjacent network devices.
19.4R3-S11, 20.2R3-S7, 20.3R3-S6, 20.4R3-S6, 21.1R3-S4, 21.2R3-S4, 21.3R3-S3, 21.4R3-S2, 22.1R2-S2, 22.1R3, 22.2R2, 22.3R1-S2, or 22.3R2 (depending on which branch is currently running)
- 1. Identify the current Junos OS version on the MX Series device using 'show version'
- 2. Based on the current version, determine the appropriate target fixed release from the Juniper advisory
- 3. For 19.4.x versions: upgrade to 19.4R3-S11 or later
- 4. For 20.2.x versions: upgrade to 20.2R3-S7 or later
- 5. For 20.3.x versions: upgrade to 20.3R3-S6 or later
- 6. Download the appropriate upgrade package from the Juniper support portal
- 7. Upload the upgrade package to the device using 'file copy' or USB
- 8. Install the upgrade using 'request system software add <package> reboot'
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2023-28974 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-28974 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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