CVE-2020-1617

CVE-2020-1617 is a high-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-665.

Key facts

Description

This issue occurs on Juniper Networks Junos OS devices which do not support Advanced Forwarding Interface (AFI) / Advanced Forwarding Toolkit (AFT). Devices using AFI and AFT are not exploitable to this issue. An improper initialization of memory in the packet forwarding architecture in Juniper Networks Junos OS non-AFI/AFT platforms which may lead to a Denial of Service (DoS) vulnerability being exploited when a genuine packet is received and inspected by non-AFT/AFI sFlow and when the device is also configured with firewall policers. This first genuine packet received and inspected by sampled flow (sFlow) through a specific firewall policer will cause the device to reboot. After the reboot has completed, if the device receives and sFlow inspects another genuine packet seen through a specific firewall policer, the device will generate a core file and reboot. Continued inspection of these genuine packets will create an extended Denial of Service (DoS) condition. Depending on the method for service restoration, e.g. hard boot or soft reboot, a core file may or may not be generated the next time the packet is received and inspected by sFlow. This issue affects: Juniper Networks Junos OS 17.4 versions prior to 17.4R2-S9, 17.4R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.1 versions prior to 18.1R3-S9 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2X75 versions prior to 18.2X75-D12, 18.2X75-D30 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2 versions prior to 18.2R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.3 versions prior to 18.3R3 on PTX1000 and PTX10000 Series, QFX10000 Series. This issue is not applicable to Junos OS versions before 17.4R1. This issue is not applicable to Junos OS Evolved or Junos OS with Advanced Forwarding Toolkit (AFT) forwarding implementations which use a different implementation of sFlow. The following example information is unrelated to this issue and is provided solely to assist you with determining if you have AFT or not. Example: A Junos OS device which supports the use of EVPN signaled VPWS with Flexible Cross Connect uses the AFT implementation. Since this configuration requires support and use of the AFT implementation to support this configuration, the device is not vulnerable to this issue as the sFlow implementation is different using the AFT architecture. For further details about AFT visit the AFI / AFT are in the links below. If you are uncertain if you use the AFI/AFT implementation or not, there are configuration examples in the links below which you may use to determine if you are vulnerable to this issue or not. If the commands work, you are. If not, you are not. You may also use the Feature Explorer to determine if AFI/AFT is supported or not. If you are still uncertain, please contact your support resources.

Frequently asked questions

What is CVE-2020-1617?
This issue occurs on Juniper Networks Junos OS devices which do not support Advanced Forwarding Interface (AFI) / Advanced Forwarding Toolkit (AFT). Devices using AFI and AFT are not exploitable to this issue. An improper initialization of memory in the packet forwarding architecture in Juniper Networks Junos OS non-AFI/AFT platforms which may lead to a Denial of Service (DoS) vulnerability being exploited when a genuine packet is received and inspected by non-AFT/AFI sFlow and when the device is also configured with firewall policers. This first genuine packet received and inspected by sampled flow (sFlow) through a specific firewall policer will cause the device to reboot. After the reboot has completed, if the device receives and sFlow inspects another genuine packet seen through a specific firewall policer, the device will generate a core file and reboot. Continued inspection of these genuine packets will create an extended Denial of Service (DoS) condition. Depending on the method for service restoration, e.g. hard boot or soft reboot, a core file may or may not be generated the next time the packet is received and inspected by sFlow. This issue affects: Juniper Networks Junos OS 17.4 versions prior to 17.4R2-S9, 17.4R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.1 versions prior to 18.1R3-S9 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2X75 versions prior to 18.2X75-D12, 18.2X75-D30 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.2 versions prior to 18.2R3 on PTX1000 and PTX10000 Series, QFX10000 Series; 18.3 versions prior to 18.3R3 on PTX1000 and PTX10000 Series, QFX10000 Series. This issue is not applicable to Junos OS versions before 17.4R1. This issue is not applicable to Junos OS Evolved or Junos OS with Advanced Forwarding Toolkit (AFT) forwarding implementations which use a different implementation of sFlow. The following example information is unrelated to this issue and is provided solely to assist you with determining if you have AFT or not. Example: A Junos OS device which supports the use of EVPN signaled VPWS with Flexible Cross Connect uses the AFT implementation. Since this configuration requires support and use of the AFT implementation to support this configuration, the device is not vulnerable to this issue as the sFlow implementation is different using the AFT architecture. For further details about AFT visit the AFI / AFT are in the links below. If you are uncertain if you use the AFI/AFT implementation or not, there are configuration examples in the links below which you may use to determine if you are vulnerable to this issue or not. If the commands work, you are. If not, you are not. You may also use the Feature Explorer to determine if AFI/AFT is supported or not. If you are still uncertain, please contact your support resources.
How severe is CVE-2020-1617?
CVE-2020-1617 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-1617 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1617?
CVE-2020-1617 primarily affects Juniper Junos. In total, 52 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-1617?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-1617 published?
CVE-2020-1617 was published on 2020-04-08 and last updated on 2026-06-17.

References

Affected products (52)

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