Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-59710

MEDIUM · 6.1 CVSS v3.1 Published 2026-07-06
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Patch available 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-79

Untrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.

General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Recommended fix Moderate confidence

Latest stable release after commit e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edf

  1. 1. Identify the current version of showdown in use by checking package.json or running `npm list showdown`
  2. 2. Navigate to the showdown GitHub repository at https://github.com/showdownjs/showdown
  3. 3. Locate the commit e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edf in the repository history to understand the security fix applied to src/subParsers/makehtml/tables.js
  4. 4. Upgrade to the latest stable release that includes this fix by running `npm install showdown@latest`
  5. 5. Alternatively, check release notes or tags to find the specific version that incorporated commit e5cab1e9
  6. 6. Verify the fix is applied by testing markdown with table headers containing double-quote characters (e.g., `| \"test<script>alert(1)</script>\" |`) and confirming no XSS executes

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59710 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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