CVE-2026-39857
Vulnerability Scoring
Security assessments indicate that CVE-2026-39857 presents a notable risk, potentially requiring prompt mitigation.
Security assessments indicate that CVE-2026-39857 presents a notable risk, potentially requiring prompt mitigation.
Status: Received on 15 Apr 2026, 20:16 UTC
Last updated: 🕑 16 Apr 2026, 14:16 UTC
Originally published on: 🕗 15 Apr 2026, 20:16 UTC
CVSS Release: version 3
security-advisories@github.com
Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVE-2026-39857: ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain an authorization bypass vulnerability in the choices and counts query parameters of the REST API, where these query builders execute MongoDB distinct() operations that bypass the publicApiProjection restrictions intended to limit which fields are exposed publicly. The choices and counts parameters are processed via applyBuildersSafely before the projection is applied, and MongoDB's distinct operation does not respect projections, returning all distinct values directly. The results are returned in the API response without any filtering against publicApiProjection or removeForbiddenFields. An unauthenticated attacker can extract all distinct field values for any schema field type that has a registered query builder, including string, integer, float, select, boolean, date, slug, and relationship fields. Fields protected with viewPermission are similarly exposed, and the counts variant additionally reveals how many documents have each distinct value. Both the piece-type and page REST APIs are affected. This issue has been fixed in version 4.29.0.
The exploitability of CVE-2026-39857 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
With low attack complexity and no required privileges, CVE-2026-39857 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2026-39857, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2026-39857, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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