CVE intelligence and bounded remediation

CVE-2026-33400 — Wallos is an open-source, self-hostable personal subscription tracker

Medium CVSS 5.4

Wallos is an open-source, self-hostable personal subscription tracker. Prior to version 4.7.0, a stored cross-site scripting (XSS) vulnerability in the payment method rename endpoint allows any authenticated user to inject arbitrary JavaScript that executes when any user visits the Settings, Subscriptions, or Statistics pages. Combined with the wallos_login authentication cookie lacking the HttpOnly flag, this enables full session hijacking. This issue has been patched in version 4.7.0.

Severity
Medium
CVSS
5.4 (3.1)
Published
2026-03-24
CISA KEV
Not currently listed
Ecosystem
javascript/npm
Weaknesses
CWE-79

Affected products

  • wallosapp / wallos

Matched remediation archetype

Cross-site scripting and unsafe browser output

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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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