CVE-2020-1626
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 · uneditedA vulnerability in Juniper Networks Junos OS Evolved may allow an attacker to cause a Denial of Service (DoS) by sending a high rate of specific packets to the device, resulting in a pfemand process crash. The pfemand process is responsible for packet forwarding on the device. By continuously sending the packet flood, an attacker can repeatedly crash the pfemand process causing a sustained Denial of Service. This issue can only be triggered by traffic sent to the device. Transit traffic does not cause this issue. This issue affects all version of Junos OS Evolved prior to 19.1R1-EVO.
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 confidenceDenial of Service vulnerability in Juniper Networks Junos OS Evolved where an attacker can crash the pfemand (packet forwarding manager) process by sending a high rate of specific packets directly to the device. The pfemand process handles packet forwarding and can be repeatedly crashed, causing sustained DoS. Only traffic destined TO the device triggers this issue, not transit 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= 18.3CVSS 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
- 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 the Junos OS variantRun 'show version' or check device documentation to confirm the device is running Junos OS Evolved, not standard Junos OS. This vulnerability affects only the Evolved variant.Affected if The device is running standard Junos OS instead of Junos OS Evolved - then it is NOT affected by this specific CVE.
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Determine the exact software versionExecute 'show version' or 'show version detail' to obtain the installed Junos OS Evolved version number.Affected if The installed version is exactly 18.3 - this is the affected version. Versions before 18.3 or after (such as 19.1R1-EVO and later) are NOT affected.
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Verify pfemand process statusExecute 'show system processes' or equivalent command to check if the pfemand (packet forwarding manager) process is running on the device.Affected if The pfemand process is present and running - this is the process that can be crashed by the attack.
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Assess network exposureReview network configuration and firewall rules to determine if the device is directly reachable from untrusted networks. Check if external traffic destined to the device is permitted.Affected if The device has direct exposure to untrusted/traffic where an attacker could send packets directly to it - this is required for the attack to be exploitable. Devices behind proper filtering/rate-limiting are at lower risk.
A device is affected if it runs Junos OS Evolved version 18.3, has the pfemand process, and is directly reachable by potential attackers on the network.
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 to Junos OS Evolved 19.1R1-EVO or later. If immediate upgrade is not feasible, implement filtering or rate-limiting for external traffic destined to the device to reduce attack surface.
- Consultation4.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-1626 — 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-2020-1626 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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