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Fencer Intel
medium 5.9

CVE-2026-49858 json

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

published 4mo ago modified 4mo ago also EUVD-2026-41129 , GHSA-pjhx-3c3w-9v23

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist api-platform/core 4.1.29, 4.2.25, 4.3.8
  • packagist api-platform/json-api 4.1.29, 4.2.25, 4.3.8
  • packagist api-platform/hal 4.1.29, 4.2.25, 4.3.8
  • api-platform core 4.1.29, 4.2.25, 4.3.8

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
packagist api-platform/core
>=2.6.0, <4.1.29
>=4.2.0, <4.2.25
>=4.3.0, <4.3.8
4.1.29
4.2.25
4.3.8
packagist api-platform/json-api
>=4.0.0, <4.1.29
>=4.2.0, <4.2.25
>=4.3.0, <4.3.8
4.1.29
4.2.25
4.3.8
packagist api-platform/hal
>=4.0.0, <4.1.29
>=4.2.0, <4.2.25
>=4.3.0, <4.3.8
4.1.29
4.2.25
4.3.8

Affected products

  • api-platform core
  • api-platform api-platform/hal
  • api-platform api-platform/json-api

Classification

Weakness
  • CWE-524 Use of Cache Containing Sensitive Information
  • CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.