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Fencer Vulns
high 7.5

CVE-2026-16221 json

fast-uri vulnerable to host confusion via literal backslash authority delimiter

published 2026-07-19 3 mo ago modified 2026-09-10 1 mo ago also GHSA-v2hh-gcrm-f6hx , EUVD-2026-45551

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

Impact: fast-uri versions from 2.3.1 through 4.1.0 (including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2) do not treat a literal backslash character (U+005C) as an authority delimiter. Node's native WHATWG URL parser, used by fetch, undici, and Node's http and https clients, normalizes the backslash to a forward slash for special schemes such as http, https, ws, wss, ftp, and file. As a result, the two parsers extract different hosts from the same input string. Applications that use fast-uri to enforce host-based policy such as allowlists, denylists, loopback or SSRF filtering, redirect validation, or outbound proxy routing before passing the same URL into Node's URL or fetch consumers can be steered to an unintended destination, including cloud metadata endpoints, loopback, or internal hosts.

Patches: upgrade to fast-uri 4.1.1, 3.1.4, or 2.4.3.

Workarounds: none.

Patch / fix

  • npm fast-uri 2.4.3, 3.1.4, 4.1.1
  • fast-uri fast-uri 2.4.3, 3.1.4, 4.1.1
  • node-ajv Debian 14 8.20.0~ds+~cs7.1.2-1

debian advisories DEBIAN-CVE-2026-16221

  • grafana12.4 hummingbird 1 12.4.8-0.1.1.hum1
  • grafana13.1 hummingbird 1 13.1.3-0.1.1.hum1

red hat advisories RHSA-2026:54518RHSA-2026:54517

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-16221 updated cvss 7.5

fast-uri: Fast-uri: Security policy bypass due to URL parsing inconsistency

  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-console-plugin-rhel9, openshift-lightspeed/lightspeed-agentic-console-rhel9, openshift-lightspeed/lightspeed-console-plugin-419-rhel9, openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9 Red Hat OpenShift Serverless openshift-serverless-1/kn-eventing-integrations-transform-jsonata-rhel9 Red Hat build of Apicurio Registry 3 apicurio/apicurio-registry-ui-rhel8, apicurio/apicurio-registry-ui-rhel9 Red Hat Connectivity Link 1 rhcl-1/rhcl-console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/disk-image-cuda-rhel9
    affected: workaround, no fix available, no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-agent-installer-ui-rhel9 Red Hat OpenShift Container Platform 5 openshift5/nmstate-console-plugin-rhel9
    affected: workaround, no fix available
  • Red Hat Multicluster Engine for Kubernetes multicluster-engine/console-mce-rhel9 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/console-rhel9 Red Hat Ansible Automation Platform 2 automation-gateway, automation-platform-ui, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-27/gateway-rhel9, ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, +3 more Red Hat Discovery 2 discovery/discovery-ui-rhel9 Red Hat Edge Manager 1 rhem/flightctl-ui-rhel9, rhem/flightctl-ui-rhel10, rhem/flightctl-ui-ocp-rhel9, rhem/flightctl-ui-ocp-rhel10 Red Hat Enterprise Linux 8 dotnet, dotnet8.0, dotnet-host, dotnet-sdk-8.0, dotnet-hostfxr-8.0, dotnet-runtime-8.0, +10 more
    +5 more products
    Red Hat Enterprise Linux 9 sgx-mpa, tdx-qgs, sgx-libs, sgx-pccs, linux-sgx, sgx-common, +2 more Red Hat Enterprise Linux 10 linux-sgx Red Hat Satellite 6 nodejs-webpack, nodejs-mini-css-extract-plugin, satellite/iop-remediations-rhel9, nodejs-compression-webpack-plugin, satellite/iop-advisor-frontend-rhel9, satellite/iop-vulnerability-frontend-rhel9, +1 more Red Hat Secrets Management Console for Red Hat OpenShift external-secrets-management/console-plugin-rhel9 Red Hat Self-service automation portal 2 ansible-automation-platform/automation-portal, ansible-automation-platform/bootc-automation-portal-rhel9
    under investigation
  • Red Hat Hardened Images grafana12.4 12.4.8-0.1.1.hum1, grafana13.1 13.1.3-0.1.1.hum1
    fixed: vendor fix RHSA-2026:54518
  • Red Hat Migration Toolkit 1.8 rhmtc/openshift-migration-ui-rhel8 1789546373
    fixed: vendor fix RHSA-2026:68681
  • Red Hat OpenShift AI 2.25 rhoai/odh-mod-arch-model-registry-rhel9 1791853432
    fixed: vendor fix RHSA-2026:87410
  • Red Hat OpenShift AI 3.3 rhoai/odh-mod-arch-gen-ai-rhel9 1790128173
    fixed: vendor fix RHSA-2026:73987
show 13 more
  • Red Hat OpenShift AI 3.4 rhoai/odh-dashboard-rhel9 1791861020, rhoai/odh-mod-arch-maas-rhel9 1791860708, rhoai/odh-feature-server-rhel9 1791863220, rhoai/odh-mod-arch-automl-rhel9 1791861032, rhoai/odh-mod-arch-gen-ai-rhel9 1793001896, rhoai/odh-mod-arch-mlflow-rhel9 1791861383, +3 more
    fixed: vendor fix RHSA-2026:84734
  • Red Hat OpenShift Container Platform 4.21 openshift4/nmstate-console-plugin-rhel9 1789592806
    fixed: vendor fix RHSA-2026:68547
  • Red Hat OpenShift Container Platform 4.22 openshift4/nmstate-console-plugin-rhel9 1789567849
    fixed: vendor fix RHSA-2026:68553
  • Red Hat Openshift Data Foundation 4.22 odf4/cephcsi-rhel9 1788162216, odf4/odf-cli-rhel9 1788163238, odf4/mcg-core-rhel9 1788162644, odf4/odf-drbd-rhel9 1788163607, odf4/odf-console-rhel9 1788164027, odf4/devicefinder-rhel9 1788162237, +22 more
    fixed: vendor fix RHSA-2026:65130
  • Red Hat Quay 3.9 quay/quay-rhel8 1788595574
    fixed: vendor fix RHSA-2026:65514
  • Red Hat Quay 3.14 quay/quay-rhel8 1788593843
    fixed: vendor fix RHSA-2026:70267
  • Red Hat Quay 3.16 quay/quay-rhel9 1789563753
    fixed: vendor fix RHSA-2026:69255
  • Red Hat Quay 3.17 quay/quay-rhel9 1790690298
    fixed: vendor fix RHSA-2026:74511
  • Red Hat Quay 3.18 quay/quay-rhel9 1791265590
    fixed: vendor fix RHSA-2026:81110
  • Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9
    not affected: component not present
  • Red Hat Network Observability Operator network-observability/network-observability-console-plugin-rhel9, network-observability/network-observability-console-plugin-pf5-rhel9 Red Hat OpenShift Pipelines openshift-pipelines/pipelines-hub-ui-rhel8, openshift-pipelines/pipelines-hub-ui-rhel9, openshift-pipelines/pipelines-console-plugin-rhel8, openshift-pipelines/pipelines-console-plugin-rhel9, openshift-pipelines/pipelines-console-plugin-pf5-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift Serverless openshift-serverless-1/kn-eventing-integrations-log-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9, openshift-serverless-1/kn-eventing-integrations-timer-source-rhel9, openshift-serverless-1/kn-eventing-integrations-aws-s3-source-rhel9, +2 more
    not affected: component not present
  • Red Hat AMQ Broker 7 amq-broker-bin.zip, amq-broker-maven-repository.zip Red Hat build of Apache Camel - HawtIO 4 rhaf-hawtio-maven-repository.zip 4.4.0.GA Red Hat Build of Podman Desktop rh-podman-desktop.git Red Hat Data Grid 8 redhat-datagrid-maven-repository.zip
    not affected: vulnerable code not present

18 more not affected in the full advisory

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm fast-uri
>=2.3.1, <2.4.3
>=3.0.0, <3.1.4
>=4.0.0, <4.1.1
2.4.3
3.1.4
4.1.1

Affected products

  • fast-uri fast-uri

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.