CVE intelligence and bounded remediation
CVE-2026-34429 — Vvveb security vulnerability
Vvveb prior to 1.0.8.1 contains a stored cross-site scripting vulnerability that allows authenticated users with media upload and rename permissions to execute arbitrary JavaScript by bypassing MIME type validation and renaming uploaded files to executable extensions. Attackers can prepend a GIF89a header to HTML/JavaScript payloads to bypass upload validation, rename the file to .html extension, and execute malicious scripts in an administrator's browser session to create backdoor accounts and upload malicious plugins for remote code execution.
- Severity
- Medium
- CVSS
- 5.4 (3.1)
- Published
- 2026-04-20
- CISA KEV
- Not currently listed
- Ecosystem
- javascript/npm
- Weaknesses
- CWE-79
Affected products
No browser-safe affected-product rows are available.
Matched remediation archetype
Cross-site scripting and unsafe browser output
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
- Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
- Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.
Remediate safely
- Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
- Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
- Update affected rendering components and add tests for every output context using inert sentinel markup.
Authoritative sources
Complete CVE record and remediation plan
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