Status: Resolved

Impact Window: Recently detected and remediated

Components: HTML Coding System (auto-generation of HTML/CSS/JS), Ceodex model integration

Severity: Medium (content integrity + limited security risk in specific edge cases)

A bug in ZentraCore AI’s HTML Coding System caused some auto-generated pages to ship with malformed markup and, in rare cases, insufficient sanitization of dynamic attributes. This could break layouts and—under very specific user-supplied inputs—allow unsafe HTML to render. We’ve fixed the issue, re-generated affected outputs, added stricter sanitization, and expanded our tests. No credentials or payment data were exposed.

Our HTML Coding System converts model output (Ceodex and other sub-models) into ready-to-use HTML/CSS/JS. A regression in the post-processing pipeline did two things:

• Tag-balancing error: Closing tags could be dropped when nested components were combined, leading to broken structure and styles.

• Attribute sanitization gap (edge case): When user-provided strings were injected into certain HTML attribute values (e.g., alt, data-*), our sanitizer correctly escaped angle brackets but did not consistently neutralize event-handler substrings if preceded by encoded characters. This made rendered HTML incorrect in most cases, and theoretical XSS possible if a developer pasted the raw output into a production page without further review.

Important: We found no evidence of credential leakage, authorization bypass, or access to customer data. The issue was limited to generated front-end code quality and a narrow sanitization loophole.

• Who was affected: Developers who used the HTML Coding System to generate components/pages and pasted code directly into production without additional linting or sanitization.

• What users saw: Broken layouts (misaligned sections, missing footers), invalid HTML warnings, or inconsistent behavior in certain browsers.

• Security exposure: Low likelihood; required a crafted input and direct use of raw generated markup. We have no reports of exploitation.

• Detection: Anomalies in generated DOM structure surfaced during internal QA and community reports.

• Mitigation: We temporarily disabled risky template merges and forced strict escaping for all dynamic attributes.

• Remediation: Deployed a fix for tag-balancing, upgraded the sanitizer to block encoded event handlers, and re-generated recent outputs.

• Validation: Added regression tests, fuzzed attribute values, and verified across major browsers.

(Specific timestamps available to enterprise customers upon request.)

• A refactor introduced non-associative merges in the component composer. When two nested fragments both requested trimming of trailing whitespace before a closing tag, the composer sometimes omitted the closing tag entirely.

• Our sanitizer pipeline assumed post-escape strings could not reassemble into event handler tokens (e.g., onerror) via mixed encoding. In an edge pattern, partial decoding by the browser could reconstitute the token inside an attribute context.

• Deterministic composer: Enforced associative concatenation with an AST-based HTML builder; tag balance is now guaranteed.

• Hardened sanitizer:

  • Blocks event handler tokens in attributes regardless of encoding/mixed-case.

  • Normalizes & re-escapes before final emission.

  • Denies javascript: and similar dangerous URL schemes even if obfuscated.

• Safer defaults: Generated code now includes a Content Security Policy (CSP) snippet recommendation and rel="noopener" for outbound links.

• Test coverage: Added fuzz tests for attributes, nested templates, and browser-level decoding quirks.

• Developer warnings: The UI now flags when user-provided strings are interpolated and links to secure-by-default patterns.

• If you deployed generated code between the noted window:

  • Re-generate with the updated HTML Coding System and redeploy.

  • Enable a restrictive CSP (e.g., no inline scripts unless hashed).

  • Run your build through an HTML validator and a security linter.

• If you only prototyped locally or reviewed the code: No action is typically required.

• AST-only rendering: No string-based concatenation in the final render path.

• Defense in depth: Sanitization, validation, and CSP suggestions are baked in.

• Red-team fuzzing: Continuous fuzz tests on attributes and encodings.

• Gate checks: Any sanitizer change now requires security review and paired approval.

Was customer data exposed?

No. This issue affected generated front-end code, not stored customer data or auth.

Could this be exploited?

Only under narrow conditions involving crafted input and direct use of raw generated HTML. We have no evidence of abuse.

Does this affect Ceodex “Pro” vs “Base”?

Both used the same post-processor; the fix applies platform-wide.

Will my credits be refunded for broken generations?

If you were impacted, contact support; we’ll make it right.

• Security: security@zentracoreintell.com

• Support: support@zentracoreintell.com

Thank you to community members and customers who reported DOM irregularities and helped us validate the fix. We’re committed to safe-by-default code generation and transparent communication.