How severe is CVE-2021-0248?

CVE-2021-0248 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-0248 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-0248?

CVE-2021-0248 primarily affects Juniper Junos. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-0248?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-0248 published?

CVE-2021-0248 was published on 2021-04-22 and last updated on 2026-06-17.

CVE-2021-0248

CVE-2021-0248 is a critical-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 10.0. 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-798.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v2: 7.5
EPSS exploit prediction: 1% (60th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-798
Affected product: Juniper Junos
Published: 2021-04-22
Last modified: 2026-06-17

Description

This issue is not applicable to NFX NextGen Software. On NFX Series devices the use of Hard-coded Credentials in Juniper Networks Junos OS allows an attacker to take over any instance of an NFX deployment. This issue is only exploitable through administrative interfaces. This issue affects: Juniper Networks Junos OS versions prior to 19.1R1 on NFX Series. No other platforms besides NFX Series devices are affected.

Frequently asked questions

What is CVE-2021-0248?: This issue is not applicable to NFX NextGen Software. On NFX Series devices the use of Hard-coded Credentials in Juniper Networks Junos OS allows an attacker to take over any instance of an NFX deployment. This issue is only exploitable through administrative interfaces. This issue affects: Juniper Networks Junos OS versions prior to 19.1R1 on NFX Series. No other platforms besides NFX Series devices are affected.
How severe is CVE-2021-0248?: CVE-2021-0248 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-0248 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (60th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-0248?: CVE-2021-0248 primarily affects Juniper Junos. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-0248?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-0248 published?: CVE-2021-0248 was published on 2021-04-22 and last updated on 2026-06-17.

References

https://kb.juniper.net/JSA11141

Affected products (2)

cpe:2.3:o:juniper:junos:*:*:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:19.1:-:*:*:*:*:*:*

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