How severe is CVE-2020-9491?

CVE-2020-9491 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2020-9491 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-9491?

CVE-2020-9491 affects Apache Nifi. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-9491?

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-2020-9491 published?

CVE-2020-9491 was published on 2020-10-01 and last updated on 2026-06-17.

CVE-2020-9491

CVE-2020-9491 is a high-severity vulnerability in Apache Nifi with a CVSS 3.x base score of 7.5. 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-327.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-327
Affected product: Apache Nifi
Published: 2020-10-01
Last modified: 2026-06-17

Description

In Apache NiFi 1.2.0 to 1.11.4, the NiFi UI and API were protected by mandating TLS v1.2, as well as listening connections established by processors like ListenHTTP, HandleHttpRequest, etc. However intracluster communication such as cluster request replication, Site-to-Site, and load balanced queues continued to support TLS v1.0 or v1.1.

Frequently asked questions

What is CVE-2020-9491?: In Apache NiFi 1.2.0 to 1.11.4, the NiFi UI and API were protected by mandating TLS v1.2, as well as listening connections established by processors like ListenHTTP, HandleHttpRequest, etc. However intracluster communication such as cluster request replication, Site-to-Site, and load balanced queues continued to support TLS v1.0 or v1.1.
How severe is CVE-2020-9491?: CVE-2020-9491 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2020-9491 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-9491?: CVE-2020-9491 affects Apache Nifi. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-9491?: 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-2020-9491 published?: CVE-2020-9491 was published on 2020-10-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:nifi:*:*:*:*:*:*:*:*

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