GHSA-22g5-r2x5-97cx is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in showdown. No vendor fix is recorded yet; mitigation options are listed below.
showdown allows stored cross-site scripting through table header ID injection
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-22g5-r2x5-97cx.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-22g5-r2x5-97cx by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 382,574 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
showdownnpmDescription
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | showdown | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for showdown, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of showdown has shipped for GHSA-22g5-r2x5-97cx yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Showdown, as integrated into Red Hat products, is susceptible to a stored cross-site scripting vulnerability. This flaw allows an attacker to inject arbitrary HTML and script-executing SVG elements by exploiting unescaped table header ID attributes within markdown. When untrusted markdown is rendered using the default…
To mitigate this vulnerability, avoid rendering untrusted markdown content within applications utilizing Showdown. If processing untrusted markdown is unavoidable, ensure that all input is thoroughly sanitized before rendering to prevent the injection of malicious HTML or script-executing elements.Source: Red Hat security advisory for GHSA-22g5-r2x5-97cx (CC BY 4.0)
Frequently Asked Questions
Is GHSA-22g5-r2x5-97cx in your dependencies?
Find it across npm, including transitive dependencies.