GHSA-5GVW-P9QM-JGWH

Vulnerability from github – Published: 2026-07-21 22:00 – Updated: 2026-08-03 20:51
VLAI
Summary
jackson-databind: @JsonView bypassed for @JsonUnwrapped container properties on deserialization
Details

Summary

UnwrappedPropertyHandler.processUnwrapped() replays the buffered JSON for a @JsonUnwrapped property by iterating its properties and calling prop.deserializeAndSet() with no prop.visibleInView(ctxt.getActiveView()) guard — the exact guard processUnwrappedCreatorProperties() received in the #5971 / GHSA-rcqc-6cw3-h962 fix, and the guard BeanDeserializer.deserializeWithUnwrapped applies to directly-matched properties. As a result, a property annotated with both @JsonView(PrivilegedView.class) and @JsonUnwrapped is written from attacker JSON even when deserializing under a more-restrictive active view.

Correction to the original framing (runtime-verified): the gap is NOT a per-field inner @JsonView (the unwrapped sub-object's own BeanDeserializer gates inner fields correctly). The unchecked gate is the view of the unwrapped CONTAINER property.

Intent proof (runtime, 2.x HEAD 21dd70dd and 3.x HEAD 7a5939d6)

An @JsonView(AdminView) property that is NOT @JsonUnwrapped → null under PublicView (correctly gated). The identical property WITH @JsonUnwrapped → fully populated (bypass). The fix the creator path already received, not applied to the regular-property method.

Impact — write-side mass-assignment / privilege escalation

@JsonView is commonly used as a write-side authorization guard: a public endpoint binds the body under readerWithView(PublicView.class) and groups privileged state in a nested object whose container property is @JsonView(AdminView). When that property is @JsonUnwrapped, an untrusted caller mass-assigns it. PoC: a self-service registration where AccountFlags{role,approved,creditBalance} is @JsonView(AdminView) @JsonUnwrapped; attacker JSON {role:ADMIN,approved:true,creditBalance:1000000} under PublicView binds all three → approved admin with arbitrary balance. The failing gate is a WRITE gate, hence integrity-high (C:N/I:H/A:N); no worse than the C:L/I:L parent and arguably higher as @JsonView-as-write-guard is the exact use case #5971/#5969 defended.

Affected

  • com.fasterxml.jackson.core:jackson-databind 2.x: confirmed bypass at 21dd70dd (== released 2.21.4 / 2.22.0 line; includes the #5973 backport). DEFAULT_VIEW_INCLUSION default=true.
  • tools.jackson.core:jackson-databind 3.x: confirmed bypass at HEAD 7a5939d6 (latest 3.x). DEFAULT_VIEW_INCLUSION default=false → the stock-config repro is the common shape where privileged inner fields are individually @JsonView(PublicView) and the developer relies on the container @JsonView(AdminView); the 3.x PoC mass-assigns role/approved/creditBalance under PublicView. (The other simultaneous report's PoC was reportedly fixed on 3.x; this distinct container-property path is not.)

Additive variants (runtime-confirmed both branches; all closed by the same one-line guard)

  • nested @JsonUnwrapped (unwrapped-in-unwrapped) — recursive bypass.
  • merge / readerWithView(...).withValueToUpdate(...) (PATCH/partial-update) — bypass; non-unwrapped merge control gates correctly.
  • builder-based deserializer (@JsonDeserialize(builder=...)) — BuilderBasedDeserializer routes through the same processUnwrapped.
  • Honest non-findings: read-side serialization correctly honors views (no leak); @JsonAnySetter+view and @JsonTypeInfo+@JsonUnwrapped are separate/unsupported behaviors, not this bug.

Fix

Add prop.visibleInView(ctxt.getActiveView()) (when MapperFeature.DEFAULT_VIEW_INCLUSION/active-view applies) to the processUnwrapped() property loop, mirroring processUnwrappedCreatorProperties(). One change closes the impact PoC + all three variants across BeanDeserializer and BuilderBasedDeserializer. Full runnable PoCs (2.x + 3.x) + variant harnesses available on request.

Severity
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "com.fasterxml.jackson.core:jackson-databind"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.21.0"
            },
            {
              "fixed": "2.21.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.4"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "tools.jackson.core:jackson-databind"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.18.8"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "com.fasterxml.jackson.core:jackson-databind"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.18.0"
            },
            {
              "fixed": "2.18.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "com.fasterxml.jackson.core:jackson-databind"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.22.0"
            },
            {
              "fixed": "2.22.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "tools.jackson.core:jackson-databind"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "3.2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-59889"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-21T22:00:43Z",
    "nvd_published_at": "2026-07-14T21:17:06Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n`UnwrappedPropertyHandler.processUnwrapped()` replays the buffered JSON for a `@JsonUnwrapped` property by iterating its properties and calling `prop.deserializeAndSet()` with **no `prop.visibleInView(ctxt.getActiveView())` guard** \u2014 the exact guard `processUnwrappedCreatorProperties()` received in the #5971 / GHSA-rcqc-6cw3-h962 fix, and the guard `BeanDeserializer.deserializeWithUnwrapped` applies to directly-matched properties. As a result, a property annotated with both `@JsonView(PrivilegedView.class)` and `@JsonUnwrapped` is written from attacker JSON even when deserializing under a more-restrictive active view.\n\n**Correction to the original framing (runtime-verified):** the gap is NOT a per-field inner `@JsonView` (the unwrapped sub-object\u0027s own `BeanDeserializer` gates inner fields correctly). The unchecked gate is the **view of the unwrapped CONTAINER property**.\n\n## Intent proof (runtime, 2.x HEAD 21dd70dd and 3.x HEAD 7a5939d6)\nAn `@JsonView(AdminView)` property that is NOT `@JsonUnwrapped` \u2192 `null` under `PublicView` (correctly gated). The identical property WITH `@JsonUnwrapped` \u2192 fully populated (bypass). The fix the creator path already received, not applied to the regular-property method.\n\n## Impact \u2014 write-side mass-assignment / privilege escalation\n`@JsonView` is commonly used as a write-side authorization guard: a public endpoint binds the body under `readerWithView(PublicView.class)` and groups privileged state in a nested object whose container property is `@JsonView(AdminView)`. When that property is `@JsonUnwrapped`, an untrusted caller mass-assigns it. PoC: a self-service registration where `AccountFlags{role,approved,creditBalance}` is `@JsonView(AdminView) @JsonUnwrapped`; attacker JSON `{role:ADMIN,approved:true,creditBalance:1000000}` under `PublicView` binds all three \u2192 approved admin with arbitrary balance. The failing gate is a WRITE gate, hence integrity-high (`C:N/I:H/A:N`); no worse than the C:L/I:L parent and arguably higher as `@JsonView`-as-write-guard is the exact use case #5971/#5969 defended.\n\n## Affected\n- `com.fasterxml.jackson.core:jackson-databind` 2.x: confirmed bypass at 21dd70dd (== released 2.21.4 / 2.22.0 line; includes the #5973 backport). `DEFAULT_VIEW_INCLUSION` default=true.\n- `tools.jackson.core:jackson-databind` 3.x: confirmed bypass at HEAD 7a5939d6 (latest 3.x). `DEFAULT_VIEW_INCLUSION` default=false \u2192 the stock-config repro is the common shape where privileged inner fields are individually `@JsonView(PublicView)` and the developer relies on the container `@JsonView(AdminView)`; the 3.x PoC mass-assigns role/approved/creditBalance under PublicView. (The other simultaneous report\u0027s PoC was reportedly fixed on 3.x; this distinct container-property path is not.)\n\n## Additive variants (runtime-confirmed both branches; all closed by the same one-line guard)\n- nested `@JsonUnwrapped` (unwrapped-in-unwrapped) \u2014 recursive bypass.\n- merge / `readerWithView(...).withValueToUpdate(...)` (PATCH/partial-update) \u2014 bypass; non-unwrapped merge control gates correctly.\n- builder-based deserializer (`@JsonDeserialize(builder=...)`) \u2014 `BuilderBasedDeserializer` routes through the same `processUnwrapped`.\n- Honest non-findings: read-side serialization correctly honors views (no leak); `@JsonAnySetter`+view and `@JsonTypeInfo`+`@JsonUnwrapped` are separate/unsupported behaviors, not this bug.\n\n## Fix\nAdd `prop.visibleInView(ctxt.getActiveView())` (when `MapperFeature.DEFAULT_VIEW_INCLUSION`/active-view applies) to the `processUnwrapped()` property loop, mirroring `processUnwrappedCreatorProperties()`. One change closes the impact PoC + all three variants across `BeanDeserializer` and `BuilderBasedDeserializer`. Full runnable PoCs (2.x + 3.x) + variant harnesses available on request.",
  "id": "GHSA-5gvw-p9qm-jgwh",
  "modified": "2026-08-03T20:51:31Z",
  "published": "2026-07-21T22:00:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/FasterXML/jackson-databind/security/advisories/GHSA-5gvw-p9qm-jgwh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59889"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FasterXML/jackson-databind/issues/6060"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FasterXML/jackson-databind/pull/6056"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FasterXML/jackson-databind/commit/d627a8a86fcb062429282f79f3f256f181ed2c7b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/FasterXML/jackson-databind"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "jackson-databind: @JsonView bypassed for @JsonUnwrapped container properties on deserialization"
}



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