CVE-2026-6322 — fast-uri
HIGHCVE-2026-6322 is a high-severity (CVSS 7.5) CWE-436 vulnerability in fast-uri. A fix is available for fast-uri — see the affected versions and patch details below.
fast-uri vulnerable to host confusion via percent-encoded authority delimiters
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-2026-6322.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-6322 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 v3.1.1 and earlier decodes percent-encoded authority delimiters (%40 as @, %3A as :) inside the host component and serializes them back as raw characters. This changes the URI structure, turning a hostname into userinfo plus a different host.
For example, http://trusted.com%40evil.com/ normalizes to http://[email protected]/, which reparses as host evil.com with userinfo trusted.com.
Applications that normalize untrusted URLs before host allowlist checks, redirect validation, or outbound request routing can be steered to a different authority than the original URL appeared to contain.
Patches
Upgrade to fast-uri >= 3.1.2, or if you are in the v2.x release line, v2.4.1
Workarounds
None. Upgrade to the patched version.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | fast-uri | ≥ 3.0.0&&< 3.1.2 | 3.1.2npm install fast-uri@3.1.2 |
| 📦npm | fast-uri | all versions | 2.4.1npm install fast-uri@2.4.1 |
Detection & 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 3.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-6322 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-6322 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-6322. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
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 Important flaw in the `fast-uri` library allows an attacker to bypass security controls in Red Hat products that process Uniform Resource Identifiers (URIs). By crafting a malicious URI with percent-encoded authority delimiters, an attacker can cause the library to incorrectly interpret the URI's authority,…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Ansible Automation Platform 2.5 for RHEL 8 | automation-gateway-0:2.5.20260715-1.el8ap | RHSA-2026:42078 |
| Red Hat Ansible Automation Platform 2.6 for RHEL 9 | automation-platform-ui-0:2.6.10-1.el9ap | RHSA-2026:34160 |
| Red Hat Data Grid 8.6.2 | fast-uri | RHSA-2026:41951 |
| Red Hat Enterprise Linux 10 | rh-podman-desktop-0:1.1.1-1.el10_2 | RHSA-2026:37385 |
| Cluster Observability Operator 1.5.0 | cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9:1782840519 | RHSA-2026:34342 |
| multicluster engine for Kubernetes 2.11 | multicluster-engine/console-mce-rhel9:1780910888 | RHSA-2026:25271 |
| Red Hat Advanced Cluster Management for Kubernetes 2.16 | rhacm2/console-rhel9:1780600823 | RHSA-2026:25273 |
| Red Hat Ansible Automation Platform 2.6 | ansible-automation-platform-26/gateway-rhel9:1782761510 | RHSA-2026:34374 |
Frequently Asked Questions
Is CVE-2026-6322 in your dependencies?
O3 Security finds CVE-2026-6322 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.