# CVE-2026-13676: node-ajv: fast-uri versions 2.3.1 through 3.1.2 and 4.0.0 fail to canonicalize Unicode (IDN) hostnames for HTTP-family URLs

CVE-2026-13676 is fixed in 8 products on 1 platform, first by DEBIAN-CVE-2026-13676, released June 29, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-13676
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0069
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 29, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | agama-web-ui opensuse-leap 16.0 | 17+673.b97ba64d6-160000.12.1 | [OPENSUSE-SU-2026:21448-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21448-1.md) | Jul 27, 2026 |
| Linux | node-ajv Debian 14 | 8.20.0~ds+~cs7.1.2-1 | [DEBIAN-CVE-2026-13676](https://patchblox.com/security/data/fix/linux/debian-cve-2026-13676.md) | Jun 29, 2026 |
| Linux | python-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python-jupytext-doc Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python-pydata-sphinx-theme opensuse-leap 16.0 | 0.16.1-bp160.3.1 | [OPENSUSE-SU-2026:21231-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21231-1.md) | Jul 3, 2026 |
| Linux | python3-jupyterlab-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | python3-jupytext Fedora 43 | 1.19.6-1.fc43 | [FEDORA-2026-3942AB86FD](https://patchblox.com/security/data/fix/linux/fedora-2026-3942ab86fd.md) | Oct 5, 2026 |
| Linux | rh-podman-desktop RHEL 10 | 1.1.2-1.el10_2 | [RHSA-2026:57590](https://patchblox.com/security/data/fix/linux/rhsa-2026-57590.md) | Aug 21, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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