CVE-2026-84292 is a high-severity (CVSS 7.5) CWE-116 vulnerability in fast-uri. A fix is available for fast-uri — see the affected versions and patch details below.
fast-uri vulnerable to authority injection via an unvalidated port in serialize
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-84292.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-84292 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
fast-urinpmDescription
Impact
fast-uri serializes the port component of a URI without validating it. When recomposing the authority, fast-uri escapes the userinfo and host components but concatenates the port verbatim, so a port value that is not a sequence of digits can inject authority delimiters. For example, serializing a component whose port is @127.0.0.1:8124 produces http://trusted.example:@127.0.0.1:8124/app, demoting the intended host to userinfo and pointing the authority at an attacker-controlled host. Both fast-uri and Node's URL read the result back as the attacker's host with no error, so re-validating the built URI does not catch it.
This affects applications that build URIs from parts and assign untrusted data to the port component (for example a fixed host from configuration and a port taken from user input or a service record). The same path is reachable through serialize(), normalize(), and equal() in their object forms. A port obtained from parse() is always digits and is not affected.
Patches
This vulnerability has been patched in fast-uri 4.1.4, 3.1.7, and 2.4.6. recomposeAuthority now rejects any port that is not *DIGIT per RFC 3986. All users should upgrade.
Workarounds
If upgrading is not immediately possible, validate the port value against the RFC 3986 grammar (digits only) before passing a component to serialize(), normalize(), or equal(), and reject anything else, for example if (!/^\d*$/.test(String(port))) throw new Error('invalid port').
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fast-uri | all versions | 2.4.6npm install fast-uri@2.4.6 |
| 📦npm | fast-uri | ≥ 3.0.0&&< 3.1.7 | 3.1.7npm install fast-uri@3.1.7 |
| 📦npm | fast-uri | ≥ 4.0.0&&< 4.1.4 | 4.1.4npm install fast-uri@4.1.4 |
Affected Products
fast-uriopenjsfDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fast-uri, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update fast-uri to 2.4.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-84292 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This is an Important flaw. Applications utilizing the `fast-uri` library in Red Hat environments are susceptible to authority injection if they process untrusted data as the port component of a URI. This could allow an attacker to redirect network traffic to an arbitrary host, compromising communication integrity.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2026-84292 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | cockpit-image-builder-0:94.4-1.el10_2 | RHSA-2026:71543 |
| Red Hat Satellite 6.19 for RHEL 9 | foreman-0:3.18.0.14-1.el9sat | RHSA-2026:74503 |
| Cluster Observability Operator 1.5.3 | cluster-observability-operator/troubleshooting-panel-console-plugin-rhel9:1790854494 | RHSA-2026:74609 |
| Network Observability (NETOBSERV) 1.12.3 | network-observability/network-observability-console-plugin-pf5-rhel9:1789978780 | RHSA-2026:70593 |
| Red Hat Ansible Automation Platform 2.1 | ansible-automation-platform/automation-portal:1788775748 | RHSA-2026:65118 |
| Red Hat Ansible Automation Platform 2.2 | ansible-automation-platform/automation-portal:1788783591 | RHSA-2026:65155 |
| Red Hat Ansible Automation Platform 2.2 | ansible-automation-platform/bootc-automation-portal-rhel9:1791865660 | RHSA-2026:82151 |
| Red Hat Ansible Automation Platform 2.5 | ansible-automation-platform-25/lightspeed-rhel8:1789685837 | RHSA-2026:71210 |
Frequently Asked Questions
Is CVE-2026-84292 in your dependencies?
Find it across npm, including transitive dependencies.