Apache NiFi PMC would like to announce the discovery and resolution of 
CVE-2020-9486, CVE-2020-9487, CVE-2020-9491, and CVE-2020-13940. These issues 
have been resolved and a new version of the Apache NiFi project was released in 
accordance with the Apache Release Process. 

Apache NiFi is an easy to use, powerful, and reliable system to process and 
distribute data. It supports powerful and scalable directed graphs of data 
routing, transformation, and system mediation logic.

Fixed in Apache NiFi 1.12.0 (Released: August 18, 2020)



CVE-2020-9486: Apache NiFi information disclosure in logs

Severity: Important

Versions Affected: Apache NiFi 1.10.0 - 1.11.4

Description: The NiFi stateless execution engine produced log output which 
included sensitive property values. When a flow was triggered, the flow 
definition configuration JSON was printed, potentially containing sensitive 
values in plaintext.

Mitigation: Implemented Argon2 secure hashing to provide a deterministic 
loggable value which does not reveal the sensitive value. Users running any 
previous NiFi release should upgrade to the latest release.

Credit: This issue was discovered by Andy LoPresto and Pierre Villard.



CVE-2020-9487: Apache NiFi denial of service

Severity: Important

Versions Affected: Apache NiFi 1.0.0 - 1.11.4

Description: The NiFi download token (one-time password) mechanism used a fixed 
cache size and did not authenticate a request to create a download token, only 
when attempting to use the token to access the content. An unauthenticated user 
could repeatedly request download tokens, preventing legitimate users from 
requesting download tokens.

Mitigation: Disabled anonymous authentication, implemented a multi-indexed 
cache, and limited token creation requests to one concurrent request per user. 
Users running any previous NiFi release should upgrade to the latest release.

Credit: This issue was discovered by Dennis Detering (IT Security Consultant at 
Spike Reply).



CVE-2020-9491: Apache NiFi use of weak TLS protocols

Severity: Critical

Versions Affected: Apache NiFi 1.2.0 - 1.11.4

Description: 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.

Mitigation: Refactored disparate internal SSL and TLS code, reducing exposure 
for extension and framework developers to low-level primitives. Added support 
for TLS v1.3 on supporting JVMs. Restricted all incoming TLS communications to 
TLS v1.2+. Users running any previous NiFi release should upgrade to the latest 
release.

Credit: This issue was discovered by Juan Carlos Sequeiros and Andy LoPresto.



CVE-2020-13940: Apache NiFi information disclosure by XXE

Severity: Low

Versions Affected: Apache NiFi 1.0.0 - 1.11.4

Description: The notification service manager and various policy authorizer and 
user group provider objects allowed trusted administrators to inadvertently 
configure a potentially malicious XML file. The XML file has the ability to 
make external calls to services (via XXE).

Mitigation: An XML validator was introduced to prevent malicious code from 
being parsed and executed. Users running any previous NiFi release should 
upgrade to the latest release.

Credit: This issue was discovered by Matt Burgess and Andy LoPresto.

For more information: https://nifi.apache.org/security.html 
<https://nifi.apache.org/security.html>

Andy LoPresto
[email protected]
[email protected]
He/Him
PGP Fingerprint: 70EC B3E5 98A6 5A3F D3C4  BACE 3C6E F65B 2F7D EF69

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