CVE-2026-39857Public exploitNetwork attack vector

Information disclosure via projection-bypassing distinct queries

Published Apr 15, 2026 · Updated Apr 15, 2026

Authorization bypass in ApostropheCMS 4.28.0 and earlier allows remote attackers to read protected field values through REST queries. The choices and counts builders run MongoDB distinct() before publicApiProjection is applied, then return unfiltered results because distinct() ignores projections. Unauthenticated access to a piece-type or page API with publicApiProjection or viewPermission restrictions exposes unique values, while counts also exposes document totals.

CVSS severity5.3
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in ApostropheCMS 4.28.0 and earlier allows remote attackers to read protected field values through REST queries. The choices and counts builders run MongoDB distinct() before publicApiProjection is applied, then return unfiltered results because distinct() ignores projections. Unauthenticated access to a piece-type or page API with publicApiProjection or viewPermission restrictions exposes unique values, while counts also exposes document totals.

The record

CVE
CVE-2026-39857
Published
Apr 15, 2026
Updated
Apr 15, 2026
Vendor
Apostrophe Technologies
Product
ApostropheCMS
Classifications
CWE-200, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.29.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apostrophe Technologies · ApostropheCMSversion=< 4.29.0

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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