{"answers":{"affected":"2 open source packages ship an affected version, including @nuxtjs/mdc.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63671 exists.","fix":"Upgrade @nuxtjs/mdc to 0.22.1 or later.","what":"CVE-2026-63671 is a high-severity cross-site scripting vulnerability in nuxt-content mdc, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-63671 and fix it if it is affected.\n\nWhat it is: CVE-2026-63671 is a high-severity cross-site scripting vulnerability in nuxt-content mdc, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63671 exists.\n\nAffected packages and fixed versions:\n- @nuxtjs/mdc (npm): affected all versions; fixed in 0.22.1\n- @nuxtjs/mdc (npm): affected all versions; fixed in 0.22.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-63671/ (Markdown: https://insights.sbomify.com/CVE-2026-63671/index.md)","id":"CVE-2026-63671","markdown":"https://insights.sbomify.com/CVE-2026-63671/index.md","name":"CVE-2026-63671","record":{"aliases":["GHSA-mxm6-v9r6-r94c"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution"],"network_reachable":"yes","non_default_config":false,"product_category":"Nuxt MDC library","requires_auth":"none","summary":"Attackers can execute arbitrary JavaScript via untrusted Markdown by bypassing URL sanitization for SVG xlink:href and data:text/html URLs.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":8.1,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"},{"id":"CWE-184","name":"Incomplete List of Disallowed Inputs"}],"description":"MDC is a tool to take regular Markdown and write documents interacting deeply with a Vue component. Prior to 0.22.1, @nuxtjs/mdc uses parseMarkdown with allowDangerousHtml enabled by default and relies on validateProps, validateProp, and unsafeLinkPrefix to remove executable URLs from untrusted Markdown. validateProp checks only attributes named href or src, allowing an SVG xlink:href value represented as xLinkHref to retain a javascript: URL that executes in the page origin when selected. The data:text/html denylist entries are also compared against url.protocol, which is only data:, so an iframe src containing data:text/html survives sanitization and executes in an opaque origin when loaded. Plain href javascript: URLs, srcdoc, object, script, and base elements are already blocked, making these two paths specific sibling gaps in the sanitizer. This issue is fixed in version 0.22.1.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"@nuxtjs/mdc's URL sanitizer misses SVG xlink:href and data:text/html, allowing XSS from untrusted markdown at the default configuration","id":"CVE-2026-63671","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":2,"n_references":5,"next":{"headline":"Joomla Extension - regularlabs.com - Client IP spoofing vulnerability in Regular Labs conditions manager","id":"CVE-2026-63683"},"packages":[{"ecosystem":"npm","fixed":["0.22.1"],"introduced":["0"],"last_affected":[],"package":"@nuxtjs/mdc","purl":null,"source":"GHSA-mxm6-v9r6-r94c"},{"ecosystem":"npm","fixed":["0.22.1"],"introduced":["0"],"last_affected":[],"package":"@nuxtjs/mdc","purl":"pkg:npm/%40nuxtjs/mdc","source":"GHSA-mxm6-v9r6-r94c"}],"prev":{"headline":"ApostropheCMS: Mutation-XSS / allowedTags bypass via literal `\u003c/textarea/\u003e` solidus close","id":"CVE-2026-63670"},"products":["mdc"],"published":"2026-09-16","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-18","vendors":["nuxt-content"]},"summary":"Attackers can execute arbitrary JavaScript via untrusted Markdown by bypassing URL sanitization for SVG xlink:href and data:text/html URLs.","url":"https://insights.sbomify.com/CVE-2026-63671/"}