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High, CVSS 7.2amended

md-fileserver: Stored/Reflected XSS when viewing Markdown (raw HTML allowed)

CVE-2026-46492GHSA-32q2-hhr5-6qvv

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (md-fileserver 1.10.3), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
EPSS
  • CVE-2026-46492: 0.23% estimated exploitation activity in the next 30 days; percentile 14.14 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary A cross-site scripting (XSS) vulnerability exists in the application’s Markdown rendering logic. When user-supplied Markdown content is rendered, embedded raw HTML—including <script tags—is processed and injected into the resulting page without sanitization, allowing arbitrary JavaScript execution in the context of the affected domain. Details An attacker can craft malicious Markdown content containing <script tags or event handlers (e.g., <img onerror=...). When this Markdown is viewed or previewed, the embedded JavaScript executes in the victim’s browser. Vulnerable Components config.js → markdownIt: { html: true } (Lines 26–30) The Markdown renderer is explicitly configured to allow raw HTML. lib/markd.js (Lines 33–58) Renders Markdown content without sanitizing HTML, allowing unsafe tags and attributes to remain in the output. lib/pages/template.html The rendered Markdown is injected into the HTML template using <%= markdown % without sanitization or output encoding. PoC…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-32q2-hhr5-6qvv

  2. Revision 1 · created ·

    Published from osv record GHSA-32q2-hhr5-6qvv

Agent brief

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# Patch Next advisory brief: CVE-2026-46492

Advisory: md-fileserver: Stored/Reflected XSS when viewing Markdown (raw HTML allowed)
IDs: CVE-2026-46492, GHSA-32q2-hhr5-6qvv
Record: https://patchnext.com/advisories/cve-2026-46492 (revision 2, source checked 26 Oct 2026, 12:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: md-fileserver 1.10.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm md-fileserver: affected < 1.10.3; fixed in 1.10.3

## Suggested inspection (read-only)
- `npm ls md-fileserver --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on md-fileserver.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-32q2-hhr5-6qvv (OSV record GHSA-32q2-hhr5-6qvv lists affected ranges: npm md-fileserver >=0 <1.10.3 (fixed))
- Verified: https://github.com/advisories/GHSA-32q2-hhr5-6qvv (GitHub-reviewed advisory GHSA-32q2-hhr5-6qvv lists affected ranges: npm md-fileserver >=0 <1.10.3)

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