CVE-2026-33888: ApostropheCMS publicApiProjection bypass in Piece-Type REST API

CVE-2026-33888 · Severity: medium · CVSS 5.3 · Published 2026-04-15

ApostropheCMS, a popular content management system, contains a flaw in how it handles public data requests. An unauthenticated attacker can bypass security settings that are supposed to hide sensitive database fields, potentially exposing internal notes, metadata, or draft content. This could lead to the unauthorized disclosure of private information that site administrators intended to keep hidden from the public.

Technologies: ApostropheCMS, apostrophe (npm). Vendors: ApostropheCMS, npm.

Quick answers

Is CVE-2026-33888 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33888 being exploited in the wild.
How severe is CVE-2026-33888?
Medium severity, with a CVSS score of 5.3, published 15 April 2026.
Which products and versions are affected?
ApostropheCMS < 4.29.0; apostrophe (npm) < 4.29.0, SEMVER:introduced=0,fixed=4.29.0.
Is there a fix for CVE-2026-33888?
Yes. apostrophe (npm): upgrade to 4.29.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33888 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-33888?
Check whether you run ApostropheCMS or apostrophe (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • apostrophe (npm): upgrade to 4.29.0 or later
    npm install apostrophe@4.29.0

Technical details

The vulnerability exists in the `getRestQuery` method of the `@apostrophecms/piece-type` module. The method checks if a MongoDB projection is already set (`!query.state.project`) before applying the security-enforced `publicApiProjection`. Because user-supplied query parameters are processed via `applyBuildersSafely` before this check, an attacker can provide a `project` parameter in the REST API request to pre-populate the projection state. This causes the application to skip the intended security restrictions, allowing the attacker to request and receive any field on publicly queryable documents. The issue is fixed in version 4.29.0 by removing the conditional check and unconditionally applying the projection.

Affected products

  • ApostropheCMS apostrophe < 4.29.0

Identifiers

  • CVE-2026-33888
  • GHSA-xhq9-58fw-859p

Timeline

  • 2026-04-15: disclosed
  • 2026-04-15: patched: Fixed in version 4.29.0
  • 2026-04-16: advisory

References

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