How severe is CVE-2020-1666?

CVE-2020-1666 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-1666 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-1666?

CVE-2020-1666 primarily affects Juniper Junos Os Evolved. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-1666?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-1666 published?

CVE-2020-1666 was published on 2020-10-16 and last updated on 2026-06-17.

CVE-2020-1666

CVE-2020-1666 is a medium-severity vulnerability in Juniper Junos Os Evolved with a CVSS 3.x base score of 6.6. 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-613.

Key facts

Severity: Medium (CVSS 3.x base score 6.6)
CVSS v2: 7.2
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-613
Affected product: Juniper Junos Os Evolved
Published: 2020-10-16
Last modified: 2026-06-17

Description

The system console configuration option 'log-out-on-disconnect' In Juniper Networks Junos OS Evolved fails to log out an active CLI session when the console cable is disconnected. This could allow a malicious attacker with physical access to the console the ability to resume a previous interactive session and possibly gain administrative privileges. This issue affects all Juniper Networks Junos OS Evolved versions after 18.4R1-EVO, prior to 20.2R1-EVO.

Frequently asked questions

What is CVE-2020-1666?: The system console configuration option 'log-out-on-disconnect' In Juniper Networks Junos OS Evolved fails to log out an active CLI session when the console cable is disconnected. This could allow a malicious attacker with physical access to the console the ability to resume a previous interactive session and possibly gain administrative privileges. This issue affects all Juniper Networks Junos OS Evolved versions after 18.4R1-EVO, prior to 20.2R1-EVO.
How severe is CVE-2020-1666?: CVE-2020-1666 has a CVSS 3.x base score of 6.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-1666 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-1666?: CVE-2020-1666 primarily affects Juniper Junos Os Evolved. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-1666?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-1666 published?: CVE-2020-1666 was published on 2020-10-16 and last updated on 2026-06-17.

References

https://kb.juniper.net/JSA11063

Affected products (7)

cpe:2.3:o:juniper:junos_os_evolved:19.2:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.2:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.3:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.4:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.4:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:19.4:r2-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:20.1:r1:*:*:*:*:*:*

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