API Platform Core: Cross-user attribute leak in JSON:API and HAL item normalizers due to missing isCacheKeySafe gate

Description

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.

Scores

EPSS (exploitation in 30 days)

0.32% · top 75% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

• CWE-524: Use of Cache Containing Sensitive Information (opens in a new tab)All about CWE-524 and its CVEs
• CWE-639: Authorization Bypass Through User-Controlled Key (opens in a new tab)All about CWE-639 and its CVEs

Affected products

• api-platform · core

  • affected >= 2.6.0, < 4.1.29
  • affected >= 4.2.0, < 4.2.25
  • affected >= 4.3.0, < 4.3.8

• api-platform · api-platform/hal

  • affected >= 2.6.0, < 4.1.29
  • affected >= 4.2.0, < 4.2.25
  • affected >= 4.3.0, < 4.3.8

• api-platform · api-platform/json-api

  • affected >= 2.6.0, < 4.1.29
  • affected >= 4.2.0, < 4.2.25
  • affected >= 4.3.0, < 4.3.8

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Packagistapi-platform/coreGHSA-pjhx-3c3w-9v23 (opens in a new tab)
• Packagistapi-platform/halGHSA-pjhx-3c3w-9v23 (opens in a new tab)
• Packagistapi-platform/json-apiGHSA-pjhx-3c3w-9v23 (opens in a new tab)

References (1)

• https://github.com/api-platform/core/security/advisories/GHSA-pjhx-3c3w-9v23 (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-pjhx-3c3w-9v23 (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-49858](https://trackcve.app/badge/CVE-2026-49858.svg)](https://trackcve.app/cve/CVE-2026-49858)

Record last updated 2 Jul 2026, 12:20 UTC.