strapi: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-27886 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in strapi, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected strapi versions: >= 4.0.0, < 5.37.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.92% chance of exploitation within 30 days, higher than 80% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of strapi you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.2 | Critical | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in strapi
- 8.7 High severity
- 7.2 High severity
- 8.2 High severity
- 7.5 High severity
- 8.6 High severity
- 8.1 High severity
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.1 High severity
- 9.1 Critical severity
- 8.4 High severity
- 8.1 High severity
- 8.1 High severity
- 7.6 High severity
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