fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error. A host that starts with an opening bracket but does not end with a closing bracket is neither validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its policy against a string that is not the host the request reaches. The same host is carried through normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in 2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but is not a valid IPv6 literal.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an
    error. A host that starts with an opening bracket but does not end with a closing bracket is neither
    validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with
    error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different
    host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a
    redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its
    policy against a string that is not the host the request reaches. The same host is carried through
    normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in
    2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but
    is not a valid IPv6 literal. (CVE-2026-84394)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:74503 advisory.

    Red Hat Satellite is a system management solution that allows organizations     to configure and maintain their systems without the necessity to provide     public Internet access to their servers or other client systems. It     performs provisioning and configuration management of predefined standard     operating environments.

    Security Fix(es):

    * rubygem-foreman_remote_execution: command injection in job invocations via effective_user parameter     (CVE-2026-12405)
    * foreman: unauthenticated information disclosure via provisioning token validation flaw (CVE-2026-12423)
    * foreman: command injection in foreman-rake errors:fetch_log via request_id parameter (CVE-2026-12540)
    * foreman: command injection in foreman-rake database tasks (CVE-2026-12541)
    * foreman: command injection in foreman-tail (CVE-2026-12542)
    * foreman: SSTI and insecure deserialization in foreman-rake configuration (CVE-2026-12544)
    * rubygem-hammer_cli: command injection via insecure editor invocation (CVE-2026-12545)
    * python3.12-dynaconf: Dynaconf: Arbitrary code execution via Server-Side Template Injection     (CVE-2026-33154)
    * yggdrasil-worker-forwarder: Go encoding/asn1: Denial of Service via excessive recursion in Unmarshal     (CVE-2026-33818)
    * yggdrasil-worker-forwarder: Golang MIME: Denial of Service via maliciously-crafted MIME header     (CVE-2026-42504)
    * nodejs-sanitize-html: PostCSS: Information disclosure and denial of service via crafted CSS input     (CVE-2026-45623)
    * python-sqlparse: sqlparse: Denial of Service via quadratic CPU consumption in SQL parsing     (CVE-2026-54284)
    * python3.12-sqlparse: sqlparse: Denial of Service via quadratic CPU consumption in SQL parsing     (CVE-2026-54284)
    * rubygem-katello: SQL injection in Registry Proxy via labels (CVE-2026-56097)
    * rubygem-katello: improper authorization logic allows resource enumeration (CVE-2026-56098)
    * yggdrasil-worker-forwarder: Go html/template: Cross-Site Scripting via pathological input     (CVE-2026-56858)
    * yggdrasil-worker-forwarder: golang net/url: Denial of Service from quadratic complexity in path     resolution (CVE-2026-56860)
    * yggdrasil-worker-forwarder: Golang crypto/tls: Denial of Service via indefinite KeyUpdate messages     (CVE-2026-56862)
    * nodejs-connected-react-router: Immutable.js: Denial of Service due to mishandling of large index values     in List operations (CVE-2026-59879)
    * nodejs-sass: Immutable.js: Denial of Service due to mishandling of large index values in List operations     (CVE-2026-59879)
    * python-sqlparse: sqlparse: Denial of Service via inefficient SQL parsing (CVE-2026-59893)
    * python3.12-sqlparse: sqlparse: Denial of Service via inefficient SQL parsing (CVE-2026-59893)
    * python-sqlparse: sqlparse: Denial of Service via quadratic CPU consumption in comment grouping     (CVE-2026-71491)
    * python3.12-sqlparse: sqlparse: Denial of Service via quadratic CPU consumption in comment grouping     (CVE-2026-71491)
    * nodejs-css-loader: nanoid: Predictable ID generation due to integer overflow (CVE-2026-73086)
    * nodejs-sanitize-html: nanoid: Predictable ID generation due to integer overflow (CVE-2026-73086)
    * nodejs-compression-webpack-plugin: fast-uri: Server-Side Request Forgery via repeated hostname percent-     decoding (CVE-2026-75899)
    * nodejs-mini-css-extract-plugin: fast-uri: Server-Side Request Forgery via repeated hostname percent-     decoding (CVE-2026-75899)
    * nodejs-webpack: fast-uri: Server-Side Request Forgery via repeated hostname percent-decoding     (CVE-2026-75899)
    * nodejs-compression-webpack-plugin: fast-uri: Host confusion via skipped IDN canonicalization     (CVE-2026-75931)
    * nodejs-mini-css-extract-plugin: fast-uri: Host confusion via skipped IDN canonicalization     (CVE-2026-75931)
    * nodejs-webpack: fast-uri: Host confusion via skipped IDN canonicalization (CVE-2026-75931)
    * nodejs-compression-webpack-plugin: fast-uri: Server-side request forgery via malformed IPv6     normalization (CVE-2026-75975)
    * nodejs-mini-css-extract-plugin: fast-uri: Server-side request forgery via malformed IPv6 normalization     (CVE-2026-75975)
    * nodejs-webpack: fast-uri: Server-side request forgery via malformed IPv6 normalization (CVE-2026-75975)
    * python3.12-gitpython: GitPython: Arbitrary file read via TagReference.create() (CVE-2026-78679)
    * rubygem-katello: Katello Content View History API Cross-Organization Authorization Bypass     (CVE-2026-79654)
    * nodejs-compression-webpack-plugin: fast-uri: Authority Injection via Unvalidated Port Serialization     (CVE-2026-84292)
    * nodejs-mini-css-extract-plugin: fast-uri: Authority Injection via Unvalidated Port Serialization     (CVE-2026-84292)
    * nodejs-webpack: fast-uri: Authority Injection via Unvalidated Port Serialization (CVE-2026-84292)
    * nodejs-compression-webpack-plugin: fast-uri: Host confusion via unbalanced URI brackets can bypass     security policies (CVE-2026-84394)
    * nodejs-mini-css-extract-plugin: fast-uri: Host confusion via unbalanced URI brackets can bypass security     policies (CVE-2026-84394)
    * nodejs-webpack: fast-uri: Host confusion via unbalanced URI brackets can bypass security policies     (CVE-2026-84394)
    * python3.12-gitpython: GitPython: Remote Code Execution via Git directory impersonation (CVE-2026-87817)
    * foreman: Safemode Bypass leading to RCE (CVE-2026-96658)
    * foreman: Excessive Permissions for Viewer Role on Preview (CVE-2026-96659)

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an     error. A host that starts with an opening bracket but does not end with a closing bracket is neither     validated as an IP literal nor canonicalized as a domain name, so parse() returns it as the host with     error undefined, while Node's URL and the HTTP clients built on it resolve the same string to a different     host. An application that reads the parsed host to make a host decision, such as an SSRF denylist, a     redirect allowlist, or proxy routing, and then passes the original URL to an HTTP client evaluates its     policy against a string that is not the host the request reaches. The same host is carried through     normalize, equal, and resolve. This affects fast-uri versions 2.4.5, 3.1.6, and 4.1.3, and is fixed in     2.4.6, 3.1.7, and 4.1.4, where parse() reports a malformed host for any host that contains a bracket but     is not a valid IPv6 literal. (CVE-2026-84394)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
463885	Echo: fast-uri: security update to 3.1.2+echo.1	Tenable Cloud Security	Echo Local Security Checks	Local	high
463885	Echo: fast-uri: security update to 3.1.2+echo.1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
362390	RHEL 9 : Satellite 6.19.5 Async Update (Critical) (RHSA-2026:74503)	Nessus	Red Hat Local Security Checks	Local	high
448446	SCA: security update for fast-uri (GHSA-58mr-gqgx-xq4g)	Tenable Cloud Security	SCA Checks	Local	high
448446	SCA: security update for fast-uri (GHSA-58mr-gqgx-xq4g)	Tenable Self-Hosted Container Security	SCA Checks	Local	high
342553	Linux Distros Unpatched Vulnerability : CVE-2026-84394	Nessus	Misc.	Local	high

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CVE-2026-84394

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