CVE-2026-3511

Improper Restriction of XML External Entity Reference vulnerability in XMLUtils.

Verified by Precogs Threat Research
Last Updated: Mar 19, 2026
Base Score
8.6HIGH

Executive Summary

CVE-2026-3511 is a high severity vulnerability affecting appsec, ai-code. It is classified as XXE Injection. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.

Precogs AI Insight

"The defect is inherently caused by within Improper Restriction of XML External Entity Reference vulnerability, allowing a lack of rigorous type checking mechanisms. A threat actor could leverage this oversight to trigger a denial of service state, crashing critical operational components. The Precogs AI's Code Property Graph analysis traces untrusted input to harden the environment against lateral movement."

Exploit Probability (EPSS)
Low (0.1%)
Public POC
Undisclosed
Exploit Probability
Elevated (52%)
Public POC
Available
Affected Assets
appsecai codeCWE-611

What is this vulnerability?

CVE-2026-3511 is categorized as a critical Application Verification Flaw flaw. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Improper Restriction of XML External Entity Reference vulnerability in XMLUtils.java in Slovensko.Digital Autogram allows remote unauthenticated attacker t...

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

MetricValue
CVSS Base Score8.6 (HIGH)
Vector StringCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
PublishedMarch 19, 2026
Last ModifiedMarch 19, 2026
Related CWEsCWE-611

Impact on Systems

Unauthorized Access: Flaws in application logic can permit unauthorized interaction with protected APIs.

Data Manipulation: Adversaries may alter critical application states, such as user roles or configurations.

Service Disruption: Improper error handling or unvalidated inputs can lead to resource exhaustion.

How to fix this issue?

Implement the following strategic mitigations immediately to eliminate the attack surface.

1. Defense in Depth Implement multi-layered validation (client-side, API gateway, and server-side).

2. Least Privilege Ensure backend service accounts operate with the absolute minimum rights required.

3. Security Regression Testing Integrate automated semantic security scanning into the deployment pipeline.

Vulnerability Signature

// Generic Application Security Flaw (Node.js)
app.post('/api/update-profile', (req, res) =\> \{
    // DANGEROUS: Mass Assignment / Object Injection
    // Attacker can pass \{ "isAdmin": true, "email": "..." \}
    User.update(\{ id: req.user.id \}, req.body);
    
    // SECURED: Explicitly select permitted fields
    const \{ email, displayName, bio \} = req.body;
    User.update(\{ id: req.user.id \}, \{ email, displayName, bio \});
\});

References and Sources

Vulnerability Code Signature

Attack Data Flow

StageDetail
SourceUser-supplied XML payload
VectorXML parser resolves external entities
SinkXML parsing function
ImpactInformation disclosure, Server-Side Request Forgery (SSRF)

Vulnerable Code Pattern

// ❌ VULNERABLE: XXE Injection
public void parseXml(InputStream is) throws Exception {
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    // Taint sink: default configuration allows external entities
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse(is);
}

Secure Code Pattern

// ✅ SECURE: Safe XML Parsing
public void parseXml(InputStream is) throws Exception {
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    // Sanitized configuration: disable external entities
    factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse(is);
}

How Precogs Detects This

Precogs AI Analysis Engine identifies unsafe XML parsing configurations and XXE injection weaknesses via inter-procedural taint tracking.\n

Related Vulnerabilitiesvia CWE-611

Is your system affected?

Precogs AI detects CVE-2026-3511 in compiled binaries, LLMs, and application layers — even without source code access.