High severity7.5NVD Advisory· Published Jun 29, 2026· Updated Aug 13, 2026
CVE-2026-13676
CVE-2026-13676
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
43- Package: https://pypi.org/project/fast-uri
- osv-coords40 versionspkg:apk/chainguard/arangodb-3.12pkg:apk/chainguard/keep-uipkg:apk/chainguard/keep-ui-fipspkg:apk/chainguard/kibana-9.0pkg:apk/chainguard/kibana-9.0-bitnamipkg:apk/chainguard/kibana-9.0-iamguardedpkg:apk/chainguard/nextcloud-server-34pkg:apk/chainguard/opensearch-dashboards-2-dashboards-observabilitypkg:apk/chainguard/opensearch-dashboards-2-fipspkg:apk/chainguard/opensearch-dashboards-2-fips-alerting-dashboards-pluginpkg:apk/chainguard/opensearch-dashboards-2-fips-anomaly-detection-dashboards-pluginpkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-mapspkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-notificationspkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-observabilitypkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-query-workbenchpkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-reportingpkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-search-relevancepkg:apk/chainguard/opensearch-dashboards-2-fips-dashboards-visualizationspkg:apk/chainguard/opensearch-dashboards-2-fips-index-management-dashboards-pluginpkg:apk/chainguard/opensearch-dashboards-2-fips-ml-commons-dashboardspkg:apk/chainguard/opensearch-dashboards-2-fips-security-analytics-dashboards-pluginpkg:apk/chainguard/opensearch-dashboards-2-fips-security-dashboards-pluginpkg:apk/chainguard/opensearch-dashboards-3pkg:apk/chainguard/opensearch-dashboards-3-fipspkg:apk/chainguard/prismpkg:apk/chainguard/tensorflow-gpu-jupyterpkg:apk/chainguard/unleash-proxypkg:apk/chainguard/vitess-24pkg:apk/chainguard/wazuh-dashboardpkg:apk/chainguard/wazuh-dashboard-fipspkg:apk/chainguard/wazuh-dashboard-security-plugin-fipspkg:apk/chainguard/yaml-language-serverpkg:apk/wolfi/opensearch-dashboards-3pkg:apk/wolfi/prismpkg:apk/wolfi/vitess-24pkg:apk/wolfi/yaml-language-serverpkg:npm/fast-uripkg:rpm/opensuse/agama-web-ui&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/python-pydata-sphinx-theme&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/python-pydata-sphinx-theme&distro=openSUSE%20Tumbleweed
< 3.12.9.4-r15+ 39 more
- (no CPE)range: < 3.12.9.4-r15
- (no CPE)range: < 0.54.2-r1
- (no CPE)range: < 0.54.2-r2
- (no CPE)range: < 9.0.8-r34
- (no CPE)range: < 9.0.8-r34
- (no CPE)range: < 9.0.8-r34
- (no CPE)range: < 34.0.2-r5
- (no CPE)range: < 2.19.6-r8
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 2.19.5-r18
- (no CPE)range: < 3.7.0-r9
- (no CPE)range: < 3.7.0-r17
- (no CPE)range: < 5.16.0-r4
- (no CPE)range: < 0
- (no CPE)range: < 1.4.19-r2
- (no CPE)range: < 24.0.2-r7
- (no CPE)range: < 4.14.6-r8
- (no CPE)range: < 4.14.6-r5
- (no CPE)range: < 4.14.6-r5
- (no CPE)range: < 1.24.0-r1
- (no CPE)range: < 3.7.0-r9
- (no CPE)range: < 5.16.0-r4
- (no CPE)range: < 24.0.2-r7
- (no CPE)range: < 1.24.0-r1
- (no CPE)range: >= 4.0.0, < 4.0.1
- (no CPE)range: < 17+673.b97ba64d6-160000.12.1
- (no CPE)range: < 0.16.1-bp160.3.1
- (no CPE)range: < 0.19.0-2.1
Patches
Vulnerability mechanics
References
40- github.com/fastify/fast-uri/security/advisories/GHSA-4c8g-83qw-93j6nvdPatchVendor Advisory
- access.redhat.com/security/cve/CVE-2026-13676nvdThird Party Advisory
- bugzilla.redhat.com/show_bug.cginvdThird Party Advisory
- cna.openjsf.org/security-advisories.htmlnvdVendor Advisory
- github.com/advisories/GHSA-4c8g-83qw-93j6ghsaADVISORY
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-13676.jsonnvdThird Party Advisory
- access.redhat.com/errata/RHSA-2026:37186nvd
- access.redhat.com/errata/RHSA-2026:37585nvd
- access.redhat.com/errata/RHSA-2026:37628nvd
- access.redhat.com/errata/RHSA-2026:40118nvd
- access.redhat.com/errata/RHSA-2026:40262nvd
- access.redhat.com/errata/RHSA-2026:40765nvd
- access.redhat.com/errata/RHSA-2026:40945nvd
- access.redhat.com/errata/RHSA-2026:41066nvd
- access.redhat.com/errata/RHSA-2026:41928nvd
- access.redhat.com/errata/RHSA-2026:41929nvd
- access.redhat.com/errata/RHSA-2026:42815nvd
- access.redhat.com/errata/RHSA-2026:43038nvd
- access.redhat.com/errata/RHSA-2026:44239nvd
- access.redhat.com/errata/RHSA-2026:44268nvd
- access.redhat.com/errata/RHSA-2026:47728nvd
- access.redhat.com/errata/RHSA-2026:48124nvd
- access.redhat.com/errata/RHSA-2026:48126nvd
- access.redhat.com/errata/RHSA-2026:49642nvd
- access.redhat.com/errata/RHSA-2026:50340nvd
- access.redhat.com/errata/RHSA-2026:50479nvd
- access.redhat.com/errata/RHSA-2026:50758nvd
- access.redhat.com/errata/RHSA-2026:51196nvd
- access.redhat.com/errata/RHSA-2026:51197nvd
- access.redhat.com/errata/RHSA-2026:51342nvd
- access.redhat.com/errata/RHSA-2026:51348nvd
- access.redhat.com/errata/RHSA-2026:51349nvd
- github.com/fastify/fast-uri/commit/01db48010f594b98f7b323be18b393791c66ed1dghsa
- github.com/fastify/fast-uri/commit/21ea1f9d70495c931f55dff893a8fa38f4f2e6bdghsa
- github.com/fastify/fast-uri/commit/2a6d357a18a68e6d812824379fd3388a1ae50d05ghsa
- github.com/fastify/fast-uri/pull/188ghsa
- github.com/fastify/fast-uri/releases/tag/v2.4.2ghsa
- github.com/fastify/fast-uri/releases/tag/v3.1.3ghsa
- github.com/fastify/fast-uri/releases/tag/v4.0.1ghsa
- nvd.nist.gov/vuln/detail/CVE-2026-13676ghsa
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