CVE-2020-1603Network attack vector

Device crash or hang via mbuf leak

Published Jan 15, 2020 · Updated Sep 16, 2024

Denial of service in affected Juniper Networks Junos OS 16.1 through 19.2 releases allows remote attackers to crash or hang devices with IPv6 packets. The Routing Engine permits packets meant for local blocking to egress, leaking mbufs until kernel resources are exhausted. The packets must be processed by the Routing Engine; sustained delivery black-holes qualifying traffic and causes a vmcore or a hang requiring a power cycle.

CVSS severity8.6
High
EPSS probability1.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Juniper Networks Junos OS 16.1 through 19.2 releases allows remote attackers to crash or hang devices with IPv6 packets. The Routing Engine permits packets meant for local blocking to egress, leaking mbufs until kernel resources are exhausted. The packets must be processed by the Routing Engine; sustained delivery black-holes qualifying traffic and causes a vmcore or a hang requiring a power cycle.

The record

CVE
CVE-2020-1603
Published
Jan 15, 2020
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-401, CWE-710, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.1 <16.1R7-S6 changes=[{"at":"16.1X70-D10","status":"affected"}]
  2. Affected versionversion=16.2 <16.2R2-S11
  3. Affected versionversion=17.1 <17.1R2-S11, 17.1R3-S1
  4. Affected versionversion=17.2 <17.2R1-S9, 17.2R2-S8, 17.2R3-S3
  5. Affected versionversion=17.3 <17.3R3-S6
  6. Affected versionversion=17.4 <17.4R2-S9, 17.4R3
  7. Affected versionversion=18.1 <18.1R3-S7
  8. Affected versionversion=18.2 <18.2R3-S2
  9. Affected versionversion=18.2X75 <18.2X75-D50, 18.2X75-D410
  10. Affected versionversion=18.3 <18.3R1-S6, 18.3R2-S2, 18.3R3
  11. Affected versionversion=18.4 <18.4R1-S6, 18.4R2-S2, 18.4R3
  12. Affected versionversion=19.1 <19.1R1-S3, 19.1R2
  13. Affected versionversion=19.2 <19.2R1-S2, 19.2R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=16.1 <16.1R7-S6 changes=[{"at":"16.1X70-D10","status":"affected"}]; version=16.2 <16.2R2-S11; version=17.1 <17.1R2-S11, 17.1R3-S1; version=17.2 <17.2R1-S9, 17.2R2-S8, 17.2R3-S3; version=17.3 <17.3R3-S6; version=17.4 <17.4R2-S9, 17.4R3; version=18.1 <18.1R3-S7; version=18.2 <18.2R3-S2; version=18.2X75 <18.2X75-D50, 18.2X75-D410; version=18.3 <18.3R1-S6, 18.3R2-S2, 18.3R3; version=18.4 <18.4R1-S6, 18.4R2-S2, 18.4R3; version=19.1 <19.1R1-S3, 19.1R2; version=19.2 <19.2R1-S2, 19.2R2

Published CVSS scores

8.6Juniper Networks, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
7.8NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
CWE-710Improper Adherence to Coding Standards
T1499.002Endpoint Denial of Service: Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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