Is CVE-2026-39857 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-39857 being exploited in the wild.

How severe is CVE-2026-39857?

Medium severity, with a CVSS score of 5.3, published 15 April 2026.

Which products and versions are affected?

ApostropheCMS <= 4.28.0; apostrophe (npm) <= 4.28.0, SEMVER:introduced=0,fixed=4.29.0.

Is there a fix for CVE-2026-39857?

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-2026-39857 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-39857?

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.

CVE-2026-39857: ApostropheCMS information disclosure via choices and counts query parameters

Q: Which products and versions are affected?

ApostropheCMS <= 4.28.0; apostrophe (npm) <= 4.28.0, SEMVER:introduced=0,fixed=4.29.0.

Q: Is there a fix for CVE-2026-39857?

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.

Q: How is CVE-2026-39857 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-39857?

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.

CVE-2026-39857 · Severity: medium · CVSS 5.3 · Published 2026-04-15

ApostropheCMS is a content management system used to build and manage websites. A vulnerability in its web interface allows unauthenticated visitors to bypass security restrictions and view sensitive data fields that were intended to be hidden. This could lead to the exposure of internal status values, categories, or other restricted information stored within the system.

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

Quick answers

Is CVE-2026-39857 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-39857 being exploited in the wild.
How severe is CVE-2026-39857?: Medium severity, with a CVSS score of 5.3, published 15 April 2026.
Which products and versions are affected?: ApostropheCMS <= 4.28.0; apostrophe (npm) <= 4.28.0, SEMVER:introduced=0,fixed=4.29.0.
Is there a fix for CVE-2026-39857?: 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-2026-39857 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-39857?: 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

An information disclosure vulnerability exists in ApostropheCMS due to the way the REST API handles 'choices' and 'counts' query parameters. While the main API query enforces field restrictions via 'publicApiProjection' using MongoDB projections, the 'choices' and 'counts' builders use a separate code path that utilizes the MongoDB 'distinct' operation. Because 'distinct' does not respect projections, unauthenticated attackers can extract all unique values and document counts for any schema field, including those explicitly excluded from public view or protected by 'viewPermission'. This affects both the piece-type and page REST APIs. The issue is fixed in version 4.29.0.

Affected products

ApostropheCMS apostrophe <= 4.28.0

Identifiers

CVE-2026-39857
GHSA-c276-fj82-f2pq

Timeline

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

References

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