How severe is CVE-2021-0294?

CVE-2021-0294 has a CVSS 3.x base score of 5.3, rated medium 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 low.

Is CVE-2021-0294 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-0294?

CVE-2021-0294 affects Juniper Junos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-0294?

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

When was CVE-2021-0294 published?

CVE-2021-0294 was published on 2021-07-15 and last updated on 2026-06-17.

CVE-2021-0294

CVE-2021-0294 is a medium-severity vulnerability in Juniper Junos with a CVSS 3.x base score of 5.3. 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-474.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (57th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-474
Affected product: Juniper Junos
Published: 2021-07-15
Last modified: 2026-06-17

Description

A vulnerability in Juniper Networks Junos OS, which only affects the release 18.4R2-S5, where a function is inconsistently implemented on Juniper Networks Junos QFX5000 Series and EX4600 Series, and if "storm-control enhanced" is configured, can lead to the enhanced storm control filter group not be installed. It will cause storm control not to work hence allowing an attacker to cause high CPU usage or packet loss issues by sending a large amount of broadcast or unknown unicast packets arriving the device. This issue affects Juniper Networks QFX5100, QFX5110, QFX5120, QFX5200, QFX5210, EX4600, and EX4650, and QFX5100 with QFX 5e Series image installed. QFX5130 and QFX5220 are not affected from this issue. This issue affects Juniper Networks Junos OS 18.4R2-S5 on QFX5000 Series and EX4600 Series. No other product or platform is affected by this vulnerability.

Frequently asked questions

What is CVE-2021-0294?: A vulnerability in Juniper Networks Junos OS, which only affects the release 18.4R2-S5, where a function is inconsistently implemented on Juniper Networks Junos QFX5000 Series and EX4600 Series, and if "storm-control enhanced" is configured, can lead to the enhanced storm control filter group not be installed. It will cause storm control not to work hence allowing an attacker to cause high CPU usage or packet loss issues by sending a large amount of broadcast or unknown unicast packets arriving the device. This issue affects Juniper Networks QFX5100, QFX5110, QFX5120, QFX5200, QFX5210, EX4600, and EX4650, and QFX5100 with QFX 5e Series image installed. QFX5130 and QFX5220 are not affected from this issue. This issue affects Juniper Networks Junos OS 18.4R2-S5 on QFX5000 Series and EX4600 Series. No other product or platform is affected by this vulnerability.
How severe is CVE-2021-0294?: CVE-2021-0294 has a CVSS 3.x base score of 5.3, rated medium 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 low.
Is CVE-2021-0294 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (57th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-0294?: CVE-2021-0294 affects Juniper Junos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-0294?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-0294 published?: CVE-2021-0294 was published on 2021-07-15 and last updated on 2026-06-17.

References

https://kb.juniper.net/JSA11196

Affected products (1)

cpe:2.3:o:juniper:junos:18.4:r2-s5:*:*:*:*:*:*

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