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GHSA-66GJ-8QVF-QVFH

Vulnerability from github – Published: 2026-10-19 12:32 – Updated: 2026-10-19 12:32

Details

Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') vulnerability in Apache Johnzon.

ClassConverter loads & static-initializes an attacker-named class from untrusted JSON.

This issue affects Apache Johnzon: from 1.0.0 before 2.2.0.

Users are recommended to upgrade to version 1.3.1 (javax namespace) or 2.2.0 (jakarta specification namespace), which fixes the issue.

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-71253"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-470"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-19T11:17:18Z",
    "severity": null
  },
  "details": "Use of Externally-Controlled Input to Select Classes or Code (\u0027Unsafe Reflection\u0027) vulnerability in Apache Johnzon.\n\n\n\nClassConverter loads \u0026 static-initializes an attacker-named class from untrusted JSON.\n\n\n\n\nThis issue affects Apache Johnzon: from 1.0.0 before 2.2.0.\n\n\n\nUsers are recommended to upgrade to version 1.3.1 (javax namespace) or 2.2.0 (jakarta specification namespace), which fixes the issue.",
  "id": "GHSA-66gj-8qvf-qvfh",
  "modified": "2026-10-19T12:32:49Z",
  "published": "2026-10-19T12:32:49Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-71253"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apache/johnzon/commit/91e7b0d21d08d138944e2570691939739422a3d6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apache/johnzon/commit/dd3d00634c746a2173a2518e882e85e8a151bf30"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread.html/3vgm1yo2sn9yhkvvs9lc4ro01vl3zt68"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-71253 (GCVE-0-2026-71253)

Vulnerability from cvelistv5 – Published: 2026-10-19 10:36 – Updated: 2026-10-19 10:36

Title

Apache Johnzon: ClassConverter loads & static-initializes an attacker-named class from untrusted JSON

Summary

Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection') vulnerability in Apache Johnzon. ClassConverter loads & static-initializes an attacker-named class from untrusted JSON. This issue affects Apache Johnzon: from 1.0.0 before 2.2.0. Users are recommended to upgrade to version 1.3.1 (javax namespace) or 2.2.0 (jakarta specification namespace), which fixes the issue.

Severity

No CVSS data available.

CWE

CWE-470 - Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

Assigner

apache CNA under the mitre root

CNA scorecard B 76/100 over 1005 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/apache/johnzon/commit/dd3d0063…	patch
https://github.com/apache/johnzon/commit/91e7b0d2…	patch
https://lists.apache.org/thread.html/3vgm1yo2sn9y…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache Johnzon	Affected: 2.0.0 , < 2.2.0 (semver) Affected: 1.0.0 , < 1.3.1 (semver)

Credits

n0mi1k Security

Show details on NVD website

JSON

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  "containers": {
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.maven.apache.org/maven2",
          "defaultStatus": "unaffected",
          "packageName": "org.apache.johnzon:johnzon-mapper",
          "packageURL": "pkg:maven/org.apache.johnzon/johnzon-mapper",
          "product": "Apache Johnzon",
          "vendor": "Apache Software Foundation",
          "versions": [
            {
              "lessThan": "2.2.0",
              "status": "affected",
              "version": "2.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.3.1",
              "status": "affected",
              "version": "1.0.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "n0mi1k Security"
        }
      ],
      "descriptions": [
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          "lang": "en",
          "supportingMedia": [
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              "base64": false,
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            }
          ],
          "value": "Use of Externally-Controlled Input to Select Classes or Code (\u0027Unsafe Reflection\u0027) vulnerability in Apache Johnzon.\n\n\n\nClassConverter loads \u0026 static-initializes an attacker-named class from untrusted JSON.\n\n\n\n\nThis issue affects Apache Johnzon: from 1.0.0 before 2.2.0.\n\n\n\nUsers are recommended to upgrade to version 1.3.1 (javax namespace) or 2.2.0 (jakarta specification namespace), which fixes the issue."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "text": "severity: LOW. Although a class initialiser can be triggered remotely it needs 2 separate preconditions: a) there must be a poisonous class-initialiser on the classpath (unlikely). b) there must be a REST POJO with a Class attribute on the project (unlikely as well)"
            },
            "type": "Textual description of severity"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
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      "problemTypes": [
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              "lang": "en",
              "type": "CWE"
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          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T10:36:41.781Z",
        "orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
        "shortName": "apache"
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      "references": [
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          "tags": [
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          "url": "https://github.com/apache/johnzon/commit/dd3d00634c746a2173a2518e882e85e8a151bf30"
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          "url": "https://github.com/apache/johnzon/commit/91e7b0d21d08d138944e2570691939739422a3d6"
        },
        {
          "tags": [
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          "url": "https://lists.apache.org/thread.html/3vgm1yo2sn9yhkvvs9lc4ro01vl3zt68"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Apache Johnzon: ClassConverter loads \u0026 static-initializes an attacker-named class from untrusted JSON",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09",
    "assignerShortName": "apache",
    "cveId": "CVE-2026-71253",
    "datePublished": "2026-10-19T10:36:41.781Z",
    "dateReserved": "2026-08-05T11:38:30.610Z",
    "dateUpdated": "2026-10-19T10:36:41.781Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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