CVE-2020-9491

Name: CVE-2020-9491
Creator: NVD / NIST
Published: 2020-10-01T20:15:14.33+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.84%

Last modified Jun 17, 2026

CVE-2020-9491 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 2.84% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

2.84%

84.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-327

Affected Software

Vendor	Product	Versions
Apache	Nifi	>= 1.0.0, <= 1.11.4

References

Timeline

Published: Oct 1, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-9491?

How severe is CVE-2020-9491?

CVE-2020-9491 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.84% probability of exploitation in the next 30 days.

How do I fix CVE-2020-9491?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-9491?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST