How severe is CVE-2021-23021?

CVE-2021-23021 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-23021 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-23021?

CVE-2021-23021 affects F5 Nginx Controller. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-23021?

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

When was CVE-2021-23021 published?

CVE-2021-23021 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-23021

CVE-2021-23021 is a medium-severity vulnerability in F5 Nginx Controller with a CVSS 3.x base score of 5.5. 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-732.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (14th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-732
Affected product: F5 Nginx Controller
Published: 2021-06-01
Last modified: 2026-06-17

Description

The Nginx Controller 3.x before 3.7.0 agent configuration file /etc/controller-agent/agent.conf is world readable with current permission bits set to 644.

Frequently asked questions

What is CVE-2021-23021?: The Nginx Controller 3.x before 3.7.0 agent configuration file /etc/controller-agent/agent.conf is world readable with current permission bits set to 644.
How severe is CVE-2021-23021?: CVE-2021-23021 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-23021 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-23021?: CVE-2021-23021 affects F5 Nginx Controller. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-23021?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-23021 published?: CVE-2021-23021 was published on 2021-06-01 and last updated on 2026-06-17.

References

https://support.f5.com/csp/article/K36926027

Affected products (1)

cpe:2.3:a:f5:nginx_controller:*:*:*:*:*:*:*:*

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