How severe is CVE-2021-3499?

CVE-2021-3499 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2021-3499 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3499?

CVE-2021-3499 affects Ovn Ovn-kubernetes. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3499?

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

When was CVE-2021-3499 published?

CVE-2021-3499 was published on 2021-06-02 and last updated on 2026-06-17.

CVE-2021-3499

CVE-2021-3499 is a medium-severity vulnerability in Ovn Ovn-kubernetes with a CVSS 3.x base score of 5.6. 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-863.

Key facts

Severity: Medium (CVSS 3.x base score 5.6)
CVSS v2: 6.8
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Ovn Ovn-kubernetes
Published: 2021-06-02
Last modified: 2026-06-17

Description

A vulnerability was found in OVN Kubernetes in versions up to and including 0.3.0 where the Egress Firewall does not reliably apply firewall rules when there is multiple DNS rules. It could lead to potentially lose of confidentiality, integrity or availability of a service.

Frequently asked questions

What is CVE-2021-3499?: A vulnerability was found in OVN Kubernetes in versions up to and including 0.3.0 where the Egress Firewall does not reliably apply firewall rules when there is multiple DNS rules. It could lead to potentially lose of confidentiality, integrity or availability of a service.
How severe is CVE-2021-3499?: CVE-2021-3499 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2021-3499 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3499?: CVE-2021-3499 affects Ovn Ovn-kubernetes. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3499?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-3499 published?: CVE-2021-3499 was published on 2021-06-02 and last updated on 2026-06-17.

References

https://bugzilla.redhat.com/show_bug.cgi?id=1949188

Affected products (1)

cpe:2.3:a:ovn:ovn-kubernetes:*:*:*:*:*:*:*:*

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