How severe is CVE-2020-1646?

CVE-2020-1646 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-2020-1646 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-1646?

CVE-2020-1646 primarily affects Juniper Junos. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-1646?

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-2020-1646 published?

CVE-2020-1646 was published on 2020-07-17 and last updated on 2026-06-17.

CVE-2020-1646

CVE-2020-1646 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-159.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-159
Affected product: Juniper Junos
Published: 2020-07-17
Last modified: 2026-06-17

Description

On Juniper Networks Junos OS and Junos OS Evolved devices, processing a specific UPDATE for an EBGP peer can lead to a routing process daemon (RPD) crash and restart. This issue occurs only when the device is receiving and processing the BGP UPDATE for an EBGP peer. This issue does not occur when the device is receiving and processing the BGP UPDATE for an IBGP peer. However, the offending BGP UPDATE can originally come from an EBGP peer, propagates through the network via IBGP peers without causing crash, then it causes RPD crash when it is processed for a BGP UPDATE towards an EBGP peer. Repeated receipt and processing of the same specific BGP UPDATE can result in an extended Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 17.3R3-S6, 17.4R2-S7, and 18.1R3-S7. Juniper Networks Junos OS Evolved 19.2R2-EVO and later versions, prior to 19.3R1-EVO. Other Junos OS releases are not affected.

Frequently asked questions

What is CVE-2020-1646?: On Juniper Networks Junos OS and Junos OS Evolved devices, processing a specific UPDATE for an EBGP peer can lead to a routing process daemon (RPD) crash and restart. This issue occurs only when the device is receiving and processing the BGP UPDATE for an EBGP peer. This issue does not occur when the device is receiving and processing the BGP UPDATE for an IBGP peer. However, the offending BGP UPDATE can originally come from an EBGP peer, propagates through the network via IBGP peers without causing crash, then it causes RPD crash when it is processed for a BGP UPDATE towards an EBGP peer. Repeated receipt and processing of the same specific BGP UPDATE can result in an extended Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 17.3R3-S6, 17.4R2-S7, and 18.1R3-S7. Juniper Networks Junos OS Evolved 19.2R2-EVO and later versions, prior to 19.3R1-EVO. Other Junos OS releases are not affected.
How severe is CVE-2020-1646?: CVE-2020-1646 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-2020-1646 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1646?: CVE-2020-1646 primarily affects Juniper Junos. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-1646?: 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-2020-1646 published?: CVE-2020-1646 was published on 2020-07-17 and last updated on 2026-06-17.

References

https://kb.juniper.net/JSA11033

Affected products (4)

cpe:2.3:o:juniper:junos:17.3:r3-s6:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:17.4:r2-s7:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:18.1:r3-s7:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.2:r2:*:*:*:*:*:*

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