CVE-2020-1634
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 · uneditedOn High-End SRX Series devices, in specific configurations and when specific networking events or operator actions occur, an SPC receiving genuine multicast traffic may core. Subsequently, all FPCs in a chassis may reset causing a Denial of Service. This issue affects both IPv4 and IPv6. This issue affects: Juniper Networks Junos OS 12.3X48 version 12.3X48-D80 and later versions prior to 12.3X48-D95 on High-End SRX Series. This issue does not affect Branch SRX Series devices.
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 confidenceOn High-End SRX Series devices running Junos OS 12.3X48-D80 through D95, an SPC (Services Processing Card) can crash when receiving genuine multicast traffic under specific configuration states and triggering events. This core dump triggers a chassis-wide reset of all FPCs (Flexible PIC Concentrators), resulting in a complete Denial of Service affecting both IPv4 and IPv6 multicast traffic.
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= 12.3x48CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/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 device modelRun 'show chassis hardware' or check the device model to confirm it is a High-End SRX Series device (e.g., SRX5800, SRX5600, SRX5400)Affected if Device is NOT a High-End SRX Series model - the vulnerability only affects those specific platforms
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Check Junos OS versionRun 'show version' or 'show version detail' to identify the installed Junos OS versionAffected if Version is 12.3X48-D80 through 12.3X48-D95 (versions outside this range or later than D95 are not affected)
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Verify multicast traffic handling is activeRun 'show multicast interface' or 'show multicast configuration' to check if IPv4/IPv6 multicast is configured and active on the deviceAffected if Multicast protocols (e.g., PIM, IGMP, MLD) are not configured or multicast traffic is not being processed - the flaw requires active multicast traffic handling
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Confirm SPC presenceRun 'show chassis fpc' or 'show spc' to verify Services Processing Cards are installed and onlineAffected if No SPC cards are present or all SPCs are offline - the crash occurs on the SPC when processing multicast traffic
Device is affected if it is a High-End SRX Series with SPC cards, running Junos OS 12.3X48-D80 through D95, and has multicast traffic being actively processed.
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.
From vendor dataUpgrade Junos OS to version 12.3X48-D95 or later. As an interim measure, consider filtering or rate-limiting multicast traffic if not required, and ensure redundant systems are configured to minimize impact during any maintenance windows.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-1634 — 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-2020-1634 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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- Version or environment caveats, and links to real fixes
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