CVE-2026-28338 is a medium-severity (CVSS 6.8) Cross-site Scripting (XSS) vulnerability in net.sourceforge.pmd:pmd-core. A fix is available for net.sourceforge.pmd:pmd-core — see the affected versions and patch details below.
PMD Designer has Stored XSS in VBHTMLRenderer and YAHTMLRenderer via unescaped violation messages
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 CVE-2026-28338.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-28338 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
net.sourceforge.pmd:pmd-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Summary
PMD's vbhtml and yahtml report formats insert rule violation messages into HTML output without escaping. When PMD analyzes untrusted source code containing crafted string literals, the generated HTML report contains executable JavaScript that runs when opened in a browser.
While the default html format is not affected via rule violation messages (it correctly uses StringEscapeUtils.escapeHtml4()), it has a similar problem when rendering suppressed violations. The user supplied message (the reason for the suppression) was not escaped.
Details
VBHTMLRenderer.java line 71 appends rv.getDescription() directly into HTML:
sb.append("<td><font class=body>").append(rv.getDescription()).append("</font></td>");
YAHTMLRenderer.java lines 196–203 does the same via renderViolationRow():
private String renderViolationRow(String name, String value) {
return "<tr><td><b>" + name + "</b></td>" + "<td>" + value + "</td></tr>";
}
Called at line 172:
out.print(renderViolationRow("Description:", violation.getDescription()));
The violation message originates from AvoidDuplicateLiteralsRule.java line 91, which embeds raw string literal values via first.toPrintableString(). This calls StringUtil.escapeJava() (line 476–480), which is a Java source escaper — it passes <, >, and & through unchanged because they are printable ASCII (0x20–0x7e).
By contrast, HTMLRenderer.java line 143 properly escapes:
String d = StringEscapeUtils.escapeHtml4(rv.getDescription());
PoC
- Create a Java file with 4+ duplicate string literals containing an HTML payload:
public class Exploit {
String a = "<img src=x onerror=alert(document.domain)>";
String b = "<img src=x onerror=alert(document.domain)>";
String c = "<img src=x onerror=alert(document.domain)>";
String d = "<img src=x onerror=alert(document.domain)>";
}
- Run PMD with the
vbhtmlformat:
pmd check -R category/java/errorprone.xml -f vbhtml -d Exploit.java -r report.html
- Open
report.htmlin a browser. A JavaScript alert executes showingdocument.domain.
The generated HTML contains the unescaped tag:
<td><font class=body>The String literal "<img src=x onerror=alert(document.domain)>" appears 4 times in this file</font></td>
Tested and confirmed on PMD 7.22.0-SNAPSHOT (commit bcc646c53d).
Impact
Stored cross-site scripting (XSS). Affects CI/CD pipelines that run PMD with --format vbhtml or --format yahtml on untrusted source code (e.g., pull requests from external contributors) and expose the HTML report as a build artifact. JavaScript executes in the browser context of anyone who opens the report.
Practical impact is limited because vbhtml and yahtml are legacy formats rarely used in practice. The default html format has a similar issue with user messages from suppressed violations.
Fixes
- See #6475: [core] Fix stored XSS in VBHTMLRenderer and YAHTMLRenderer
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | net.sourceforge.pmd:pmd-core | all versions | 7.22.0net.sourceforge.pmd:pmd-core:7.22.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for net.sourceforge.pmd:pmd-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update net.sourceforge.pmd:pmd-core to 7.22.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28338 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-28338 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-28338. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-28338 in your dependencies?
O3 Security finds CVE-2026-28338 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.