CVE-2026-27886
CVE-2026-27886 is a security vulnerability in @strapi/strapi. O3 Security confirms whether CVE-2026-27886 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Strapi may leak sensitive data via relational filtering due to lack of query sanitization
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
@strapi/strapinpmDescription
Strapi is an open source headless content management system. Strapi versions starting in 4.0.0 and prior to 5.37.0 did not sufficiently sanitize query parameters when filtering content via relational fields. An unauthenticated attacker could use the where query parameter on any publicly-accessible content-type with an updatedBy (or other admin-relation) field to perform a boolean-oracle attack against private fields on the joined admin_users table, including the resetPasswordToken field. Extracting an admin reset token via this oracle made full administrative account takeover possible without authentication. When a filter such as where[updatedBy][resetPasswordToken][$startsWith]=a was applied to a public Content API endpoint, the underlying query generation performed a LEFT JOIN against the admin_users table and emitted a WHERE clause referencing the joined column. The query parameter sanitization layer did not block operator chains that traversed into relational target schemas the caller had no read permission on, allowing the response count to be used as a one-bit oracle on any admin-table field. The patch in version 5.37.0 introduces explicit query-parameter sanitization at the controller and service boundary via three new primitives: strictParam, addQueryParams, and addBodyParams. Operator chains that traverse into restricted relational targets are now rejected before reaching the database.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @strapi/strapi | ≥ 4.0.0&&< 5.37.0 | 5.37.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @strapi/strapi. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @strapi/strapi to 5.37.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27886 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 pinpoints whether CVE-2026-27886 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-27886. 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-2026-27886 in your dependencies?
O3 detects CVE-2026-27886 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.