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CVE-2025-66400

18
FAUCET Score

CVE-2025-66400 affects mdast-util-to-hast versions 13.0.0 through 13.2.0, allowing an attacker to inject multiple unprefixed classnames via character references in markdown source. This could lead to rendered user-supplied markdown code elements appearing as part of the legitimate page content. Rated as MEDIUM severity with a CVSS score of 5.3, this vulnerability has a low impact on integrity (I:L) and requires no user interaction (UI:N). There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 13.0.0, < 13.2.1CPE matchmatch criteria
cpe:2.3:a:unifiedjs:mdast-util-to-hast:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 4.0

6.9MEDIUM

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
LOW
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.27%
Probability of exploitation in next 30 days
EPSS Percentile
18.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0027 is in the 9th percentile among its peer group of 23,725 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (32)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: mdast-util-to-hastFixed in: 13.2.1
redhatvendor investigatingvia redhat_api
Product: Gatekeeper 3Fixed in: gatekeeper/gatekeeper-rhel9
redhatvendor investigatingvia redhat_api
Product: Migration Toolkit for Applications 7Fixed in: mta/mta-ui-rhel9
redhatvendor investigatingvia redhat_api
Product: Migration Toolkit for Applications 8Fixed in: mta/mta-ui-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift LightspeedFixed in: openshift-lightspeed/lightspeed-console-plugin-pf5-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift LightspeedFixed in: openshift-lightspeed/lightspeed-console-plugin-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-api-rhel8
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-api-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-db-migration-rhel8
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-db-migration-rhel9
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-ui-rhel8
redhatvendor investigatingvia redhat_api
Product: OpenShift PipelinesFixed in: openshift-pipelines/pipelines-hub-ui-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: ansible-automation-platform-25/aap-cloud-ui-rhel8
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: ansible-automation-platform-26/gateway-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: automation-gateway
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: automation-hub
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: automation-platform-ui
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: python3.11-galaxy-ng
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: python3x-galaxy-ng
redhatvendor investigatingvia redhat_api
Product: Red Hat Ansible Automation Platform 2Fixed in: python-galaxy-ng
redhatvendor investigatingvia redhat_api
Product: Red Hat build of Apache Camel - HawtIO 4Fixed in: io.hawt-project
redhatvendor investigatingvia redhat_api
Product: Red Hat Developer HubFixed in: rhdh/rhdh-hub-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat JBoss Enterprise Application Platform 8Fixed in: org.keycloak-keycloak-parent
redhatvendor investigatingvia redhat_api
Product: Red Hat JBoss Enterprise Application Platform Expansion PackFixed in: org.keycloak-keycloak-parent
redhatvendor investigatingvia redhat_api
Product: Red Hat OpenShift AI (RHOAI)Fixed in: rhoai/odh-dashboard-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat OpenShift AI (RHOAI)Fixed in: rhoai/odh-mod-arch-gen-ai-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat OpenShift AI (RHOAI)Fixed in: rhoai/odh-mod-arch-model-registry-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat OpenShift Container Platform 4Fixed in: openshift4/ose-agent-installer-ui-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat Quay 3Fixed in: quay/quay-rhel8
redhatvendor investigatingvia redhat_api
Product: Red Hat Satellite 6Fixed in: satellite/iop-advisor-frontend-rhel9
redhatvendor investigatingvia redhat_api
Product: Red Hat Trusted Profile AnalyzerFixed in: rhtpa/rhtpa-trustification-service-rhel9

Vendor Advisories (2)

npmGHSA-4fh9-h7wg-q85mmedium

mdast-util-to-hast has unsanitized class attribute

Dec 2, 2025
redhatCVE-2025-66400Moderate

mdast-util-to-hast: mdast-util-to-hast: Markdown code elements can appear as regular page content

Dec 1, 2025

References

github.com / syntax-tree/mdast-util-to-hast/commit/6fc783ae6abdeb798fd5a68e7f3f21411dde7403
Patch
github.com / syntax-tree/mdast-util-to-hast/commit/ab3a79570a1afbfa7efef5d4a0cd9b5caafbc5d7
Patch
github.com / syntax-tree/mdast-util-to-hast/security/advisories/GHSA-4fh9-h7wg-q85m
Vendor Advisory