Apache NiFi 0.0.1-2.9.0 Proxy Host Header Validation Vulnerability
CVE-2026-54665 Published on June 22, 2026

Apache NiFi: Missing Validation for Proxy Host Headers
Apache NiFi 0.0.1 through 2.9.0 support building qualified URLs from one of several HTTP request headers that provide an alternative to the standard Host header without validating the values provided. Apache NiFi 1.6.0 introduced a configurable application property to restrict values provided in the HTTP Host header, but did not apply the validation to alternative Proxy and Forwarded headers. The absence of proxy host header validation allowed a client to instruct Apache NiFi web services to construct invalid qualified URLs for redirection or data references. Upgrading to Apache NiFi 2.10.0 is the recommended mitigation, which implements validation for the X-ProxyHost and X-Forwarded-Host HTTP request headers based on the nifi.web.proxy.host property. Enabling header validation requires configuring the application with HTTPS. Reverse proxy servers in front of Apache NiFi are responsible for filtering input request headers and providing allowed values to the application.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-54665 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE

Timeline

reported

Weakness Type

Origin Validation Error

The software does not properly verify that the source of data or communication is valid.


Products Associated with CVE-2026-54665

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Apache NiFi
 

Affected Versions

Apache Software Foundation Apache NiFi:

Exploit Probability

EPSS
0.27%
Percentile
18.73%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.