Track vulnerabilities like this one. Sign up free to get alerted when software you use is affected.
5.9

API Platform Core may expose hidden data to other users

CVE-2026-49858 · published 4 months ago
Summary

The API Platform Core library (versions before 4.1.29, 4.2.26, and 4.3.12) can accidentally reuse information about data fields from one user’s request when serving another user, revealing attributes that should be hidden. This happens in the JSON:API and HAL response generators. Upgrade to the listed newer versions to stop the data leakage.

What to do
  • Update api-platform json-api to version 4.3.8.
  • Update api-platform hal to version 4.1.29.
  • Update api-platform core to version 4.1.29.
  • Update api-platform core to version 4.2.25.
  • Update api-platform core to version 4.3.8.
  • Update api-platform json-api to version 4.1.29.
  • Update api-platform json-api to version 4.2.25.
  • Update api-platform hal to version 4.2.25.
  • Update api-platform hal to version 4.3.8.
Affected software
Ecosystem VendorProductAffected versions
composer api-platform json-api >= 4.3.0, < 4.3.8
>= 4.0.0, < 4.1.29
>= 4.2.0, < 4.2.25
Fix: upgrade to 4.3.8
composer api-platform hal >= 4.0.0, < 4.1.29
>= 4.2.0, < 4.2.25
>= 4.3.0, < 4.3.8
Fix: upgrade to 4.1.29
composer api-platform core >= 2.6.0, < 4.1.29
>= 4.2.0, < 4.2.25
>= 4.3.0, < 4.3.8
Fix: upgrade to 4.1.29
Original advisory text
API Platform Core: Cross-user attribute leak in JSON:API and HAL item normalizers due to missing isCacheKeySafe gate
API Platform Core is a system to create hypermedia-driven REST and GraphQL APIs. In versions from 2.6.0 prior to 4.1.29, 4.2.26, and 4.3.12, a missing isCacheKeySafe gate in the JSON:API and HAL item normalizers causes a cross-user attribute leak. #[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them. This issue has been fixed in versions 4.1.29, 4.2.26, and 4.3.12.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker partial control
Severity
5.9 Medium
Exploitation
<1% chance of attack within 30 days
Type
CWE-524Use of Cache Containing Sensitive Information
CWE-639Authorization Bypass Through User-Controlled Key
Timeline
Published1 Jul 2026
Updated31 Oct 2026
First seen1 Jul 2026
Sources
CVE-2026-49858 · NVD
GHSA-pjhx-3c3w-9v23 · GHSA
CVE-2026-49858 · OSV
Track software like this
Free during beta