CVE-2026-49858

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

MEDIUM

5.9

CVSS Score

Published: July 1, 2026 at 07:24 PM UTC

Updated: July 2, 2026 at 06:58 PM UTC

3 products affected across 1 vendorCoreHALJSON:API

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Severity

MEDIUM5.9

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Core · API Platform

60%

v < 4.1.29v < 4.2.25v < 4.3.8

Affected range stops below 4.1.29, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.2.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.3.8, so it looks safe — our inference, not a vendor statement

HAL · API Platform

60%

v < 4.1.29v < 4.2.25v < 4.3.8

Affected range stops below 4.1.29, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.2.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.3.8, so it looks safe — our inference, not a vendor statement

JSON:API · API Platform

60%

v < 4.1.29v < 4.2.25v < 4.3.8

Affected range stops below 4.1.29, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.2.25, so it looks safe — our inference, not a vendor statement

Affected range stops below 4.3.8, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

x_refsource_CONFIRM

Source: cverecord

https://github.com/api-platform/core/security/advisories/GHSA-pjhx-3c3w-9v23

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMGitHub_M

Attack Vector: NETWORK
Complexity: HIGH
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: HIGH
Integrity: NONE
Availability: NONE

Vector?

Quick Info

StatusAWAITING ANALYSIS

CWE

CWE-524CWE-639

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