CVE-2026-54665
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk8th percentile — higher than 8% of all known CVEs
Summary
Apache NiFi versions 0.0.1 through 2.9.0 do not validate the values of Proxy and Forwarded headers, allowing for the construction of invalid URLs. Version 1.6.0 introduced a property to restrict Host header values, but this was not applied to alternative headers.
Risk Assessment
The lack of proxy header validation may lead to unauthorized redirections or data references, posing a risk to the application's security and user data.
Recommendation
It is recommended to upgrade to Apache NiFi version 2.10.0, which implements validation for the X-ProxyHost and X-Forwarded-Host headers. The application should also be configured with HTTPS and utilize proxy servers to filter headers.
Original NVD description (English source)
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.