# CVE-2026-13676: fast-uri vulnerable to host confusion via failed IDN canonicalization

> CVE-2026-13676: fast-uri vulnerable to host confusion via failed IDN canonicalization. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-13676
Last updated: 2026-09-11T13:17:06Z

- Published: 2026-06-29 13:22 UTC · Updated: 2026-09-11 13:17 UTC · Assigner: openjs
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- EPSS: 0.69%, 53th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-436

## Description

fast-uri versions 2.3.1 through 3.1.2 and 4.0.0 fail to canonicalize Unicode (IDN) hostnames for HTTP-family URLs. The IDN conversion path calls a helper that does not exist on the global URL constructor, silently leaving the host in its original Unicode form while normalize() and equal() still return values that differ from a WHATWG-compatible URL parser. Applications that use fast-uri to enforce host-based policy (denylists, loopback filtering, redirect validation, outbound proxy routing) before passing the same URL to Node's URL or fetch can be bypassed when the two implementations resolve the same input to different hosts. Patches: upgrade to fast-uri 3.1.3 for the 3.x line or 4.0.1 for the 4.x line. Workarounds: enforce host policy using the same URL parser used for the actual request, or reject non-ASCII hosts before policy checks.

## Affected vendors and products

- fast-uri: fast-uri
- Red Hat: Confidential Compute Attestation
- Red Hat: Cryostat 4
- Red Hat: Network Observability Operator
- Red Hat: OpenShift Lightspeed
- Red Hat: OpenShift Pipelines
- Red Hat: OpenShift Serverless
- Red Hat: Red Hat Advanced Cluster Management for Kubernetes 2.16
- Red Hat: Red Hat Advanced Cluster Management for Kubernetes 2.17
- Red Hat: Red Hat AMQ Broker 7.13.6
- Red Hat: Red Hat AMQ Broker 7.14.1
- Red Hat: Red Hat Ansible Automation Platform 2
- Red Hat: Red Hat Ansible Automation Platform 2.6
- Red Hat: Red Hat Ansible Automation Platform 2.7
- Red Hat: Red Hat build of Apache Camel - HawtIO 4
- Red Hat: Red Hat build of Apicurio Registry 3
- Red Hat: Red Hat Build of Podman Desktop
- Red Hat: Red Hat Connectivity Link 1
- Red Hat: Red Hat Data Grid 8
- Red Hat: Red Hat Enterprise Linux 10
- Red Hat: Red Hat Enterprise Linux 9
- Red Hat: Red Hat Enterprise Linux AI (RHEL AI) 3
- Red Hat: Red Hat OpenShift AI (RHOAI)
- Red Hat: Red Hat OpenShift Container Platform 4
- Red Hat: Red Hat OpenShift Virtualization 4
- Red Hat: Red Hat Satellite 6
- Red Hat: Self-service automation portal 2

## Tracked companies

- [Bitbucket](https://rewindex.com/company/bitbucket.md)
- [Confluence](https://rewindex.com/company/confluence.md)
- [Jira](https://rewindex.com/company/jira.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-13676)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-13676)
- [https://cna.openjsf.org/security-advisories.html](https://cna.openjsf.org/security-advisories.html)
- [https://github.com/fastify/fast-uri/security/advisories/GHSA-4c8g-83qw-93j6](https://github.com/fastify/fast-uri/security/advisories/GHSA-4c8g-83qw-93j6)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-13676 · Markdown: https://rewindex.com/cve/CVE-2026-13676.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-13676 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:15:36.214Z