How severe is CVE-2018-0021?

CVE-2018-0021 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-0021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-0021?

CVE-2018-0021 primarily affects Juniper Junos. In total, 61 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-0021?

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-2018-0021 published?

CVE-2018-0021 was published on 2018-04-11 and last updated on 2026-06-17.

CVE-2018-0021

CVE-2018-0021 is a high-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 3.3
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Juniper Junos
Published: 2018-04-11
Last modified: 2026-06-17

Description

If all 64 digits of the connectivity association name (CKN) key or all 32 digits of the connectivity association key (CAK) key are not configured, all remaining digits will be auto-configured to 0. Hence, Juniper devices configured with short MacSec keys are at risk to an increased likelihood that an attacker will discover the secret passphrases configured for these keys through dictionary-based and brute-force-based attacks using spoofed packets. Affected releases are Juniper Networks Junos OS: 14.1 versions prior to 14.1R10, 14.1R9; 14.1X53 versions prior to 14.1X53-D47; 15.1 versions prior to 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D100; 15.1X53 versions prior to 15.1X53-D59; 16.1 versions prior to 16.1R3-S8, 16.1R4-S8, 16.1R5; 16.2 versions prior to 16.2R1-S6, 16.2R2; 17.1 versions prior to 17.1R2.

Frequently asked questions

What is CVE-2018-0021?: If all 64 digits of the connectivity association name (CKN) key or all 32 digits of the connectivity association key (CAK) key are not configured, all remaining digits will be auto-configured to 0. Hence, Juniper devices configured with short MacSec keys are at risk to an increased likelihood that an attacker will discover the secret passphrases configured for these keys through dictionary-based and brute-force-based attacks using spoofed packets. Affected releases are Juniper Networks Junos OS: 14.1 versions prior to 14.1R10, 14.1R9; 14.1X53 versions prior to 14.1X53-D47; 15.1 versions prior to 15.1R4-S9, 15.1R6-S6, 15.1R7; 15.1X49 versions prior to 15.1X49-D100; 15.1X53 versions prior to 15.1X53-D59; 16.1 versions prior to 16.1R3-S8, 16.1R4-S8, 16.1R5; 16.2 versions prior to 16.2R1-S6, 16.2R2; 17.1 versions prior to 17.1R2.
How severe is CVE-2018-0021?: CVE-2018-0021 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-0021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-0021?: CVE-2018-0021 primarily affects Juniper Junos. In total, 61 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-0021?: 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-2018-0021 published?: CVE-2018-0021 was published on 2018-04-11 and last updated on 2026-06-17.

References

Affected products (61)

cpe:2.3:o:juniper:junos:15.1x49:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d10:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d20:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d30:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d35:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d40:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d45:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d50:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d55:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d60:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d65:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d70:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d75:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d80:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x49:d90:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r3:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r4:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r5:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r6:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r7:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1:r9:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d10:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d15:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d16:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d25:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d26:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d27:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d30:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d35:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d40:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:14.1x53:d45:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x53:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x53:d10:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x53:d20:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x53:d21:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:15.1x53:d30:*:*:*:*:*:*

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