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jackson-databind has case-insensitive deserialization bypasses per-property @JsonIgnoreProperties

Moderate severity GitHub Reviewed Published Jun 16, 2026 in FasterXML/jackson-databind • Updated Jun 23, 2026

Package

maven com.fasterxml.jackson.core:jackson-databind (Maven)

Affected versions

>= 3.1.0, < 3.1.4
>= 2.8.0, < 2.18.9
>= 2.19.0, < 2.21.5

Patched versions

3.1.4
2.18.9
2.21.5
maven tools.jackson.core:jackson-databind (Maven)
>= 3.1.0, < 3.1.4
3.1.4

Description

Summary

In BeanDeserializerBase.createContextual(), per-property @JsonIgnoreProperties exclusions are applied by _handleByNameInclusion(), producing a contextual deserializer whose BeanPropertyMap has the ignored properties removed. The subsequent per-property case-insensitivity block (triggered by @JsonFormat(ACCEPT_CASE_INSENSITIVE_PROPERTIES)) rebuilds from this._beanProperties (the original, unfiltered map) instead of contextual._beanProperties, then overwrites the filtered map — restoring every property _handleByNameInclusion had just removed. The ignored property becomes writable again.

Impact

An application that both enables case-insensitive matching and relies on per-property @JsonIgnoreProperties to keep a field unwritable can have that field set from untrusted JSON (mass-assignment-style write).

Affected / Patched

Fixed in 2.18.9, 2.21.5 and 3.1.4.

Severity / CWE

Maintainer: minor. Reporter: Moderate. CWE-915.

Upstream fix

FasterXML/jackson-databind#5962 (PR #5964, 0e1b0b2), milestone 3.1.4. Released 2026-06-04.

Credits

Omkhar Arasaratnam (@omkhar) - finder.

References

@cowtowncoder cowtowncoder published to FasterXML/jackson-databind Jun 16, 2026
Published to the GitHub Advisory Database Jun 23, 2026
Reviewed Jun 23, 2026
Last updated Jun 23, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(27th percentile)

Weaknesses

Improperly Controlled Modification of Dynamically-Determined Object Attributes

The product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified. Learn more on MITRE.

CVE ID

CVE-2026-54515

GHSA ID

GHSA-5jmj-h7xm-6q6v

Source code

Credits

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