Executive brief
A vulnerability in the Jackson data-processing library allows attackers to bypass security restrictions on Java Records. Specifically, internal data fields that were intended to be hidden or ignored can be modified by an external user if a custom naming strategy is used. This could allow an attacker to change sensitive information, such as user roles or administrative flags, that should not be accessible from the network.
Technical details
A vulnerability in jackson-databind occurs when processing Java Records using a PropertyNamingStrategy. The POJOPropertiesCollector._removeUnwantedIgnorals() method records @JsonIgnore-annotated components using their original implicit names before the naming strategy is applied via _renameUsing(). Consequently, the internal list of ignored properties contains stale names, allowing the renamed JSON keys to bypass IgnorePropertiesUtil.shouldIgnore(). An attacker can exploit this to perform mass assignment on sensitive Record fields that were intended to be ignored during deserialization. The issue is fixed in versions 2.18.8, 2.21.4, and 3.1.4.
Affected products
- FasterXML jackson-databind >= 2.15.0, < 2.18.8
- FasterXML jackson-databind >= 2.19.0, < 2.21.4
- tools.jackson.core:jackson-databind jackson-databind >= 3.0.0, < 3.1.4
Timeline
- 2026-07-10: disclosed: Initial disclosure to maintainers
- 2026-07-14: advisory: NVD publication date
- 2026-07-21: advisory: GitHub Advisory published