Object injection via unprotected API writes
Published Jul 10, 2026 · Updated Jul 10, 2026
PHP object injection in Drupal core allows remote authenticated users to inject malicious serialized data through writable JSON:API endpoints. JSON:API's write path fails to apply direct-write protection to fields that store serialized data, allowing a crafted value to reach a serialized property of an entity-reference field. Exploitation requires JSON:API write permission and a contributed or custom entity-reference field type with a serialized property; core ships no qualifying field type, and JSON:API is read-only by default.
Summary
What happened
PHP object injection in Drupal core allows remote authenticated users to inject malicious serialized data through writable JSON:API endpoints. JSON:API's write path fails to apply direct-write protection to fields that store serialized data, allowing a crafted value to reach a serialized property of an entity-reference field. Exploitation requires JSON:API write permission and a contributed or custom entity-reference field type with a serialized property; core ships no qualifying field type, and JSON:API is read-only by default.
The record
- CVE
- CVE-2026-55803
- Published
- Jul 10, 2026
- Updated
- Jul 10, 2026
- Vendor
- Avatar Uploader Project
- Product
- Drupal core
- Classifications
- CWE-915, CAPEC-586, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 10, 2026CVE publishedPublication date reported by the CVE source.
- Jul 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0.0.0 <10.5.12
- Affected versionversion=0.0.0 <11.0.*
- Affected versionversion=0.0.0 <11.1.*
- Affected versionversion=10.6.0 <10.6.11
- Affected versionversion=11.2.0 <11.2.14
- Affected versionversion=11.3.0 <11.3.12
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo