GHSA-RVV3-G6HJ-G44X

Vulnerability from github – Published: 2026-03-13 20:57 – Updated: 2026-03-25 18:53
VLAI?
Summary
AutoMapper Vulnerable to Denial of Service (DoS) via Uncontrolled Recursion
Details

Summary

AutoMapper is vulnerable to a Denial of Service (DoS) attack. When mapping deeply nested object graphs, the library uses recursive method calls without enforcing a default maximum depth limit. This allows an attacker to provide a specially crafted object graph that exhausts the thread's stack memory, triggering a StackOverflowException and causing the entire application process to terminate.

Description

The vulnerability exists in the core mapping engine. When a source object contains a property of the same type (or a type that eventually points back to itself), AutoMapper recursively attempts to map each level.

Because there is no default limit on how many levels deep this recursion can go, a sufficiently nested object (approximately 25,000+ levels in standard .NET environments) will exceed the stack size. Since StackOverflowException cannot be caught in modern .NET runtimes, the application cannot recover and will crash immediately.

Impact

  • Availability: An attacker can crash the application server, leading to a complete Denial of Service.
  • Process Termination: Unlike standard exceptions, this terminates the entire process, not just the individual request thread.

Proof of Concept (PoC)

The following C# code demonstrates the crash by creating a nested "Circular" object graph and attempting to map it:

class Circular { public Circular Self { get; set; } }

// Setup configuration
var config = new MapperConfiguration(cfg => {
    cfg.CreateMap<Circular, Circular>();
});
var mapper = config.CreateMapper();

// Create a deeply nested object (28,000+ levels)
var root = new Circular();
var current = root;
for (int i = 0; i < 30000; i++) {
    current.Self = new Circular();
    current = current.Self;
}

// This call triggers the StackOverflowException and crashes the process
mapper.Map<Circular>(root);

Recommended Mitigation

  1. Secure Defaults: Implement a default MaxDepth (e.g., 32 or 64) for all mapping operations.
  2. Configurable Limit: Allow users to increase this limit if necessary, but ensure it is enabled by default to protect unsuspecting developers.
Severity ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "AutoMapper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "16.0.0"
            },
            {
              "fixed": "16.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "AutoMapper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "15.1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32933"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-13T20:57:07Z",
    "nvd_published_at": "2026-03-20T03:16:00Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n\nAutoMapper is vulnerable to a Denial of Service (DoS) attack. When mapping deeply nested object graphs, the library uses recursive method calls without enforcing a default maximum depth limit. This allows an attacker to provide a specially crafted object graph that exhausts the thread\u0027s stack memory, triggering a `StackOverflowException` and causing the entire application process to terminate.\n\n### Description\n\nThe vulnerability exists in the core mapping engine. When a source object contains a property of the same type (or a type that eventually points back to itself), AutoMapper recursively attempts to map each level.\n\nBecause there is no default limit on how many levels deep this recursion can go, a sufficiently nested object (approximately 25,000+ levels in standard .NET environments) will exceed the stack size. Since `StackOverflowException` cannot be caught in modern .NET runtimes, the application cannot recover and will crash immediately.\n\n### Impact\n\n* **Availability:** An attacker can crash the application server, leading to a complete Denial of Service.\n* **Process Termination:** Unlike standard exceptions, this terminates the entire process, not just the individual request thread.\n\n### Proof of Concept (PoC)\n\nThe following C# code demonstrates the crash by creating a nested \"Circular\" object graph and attempting to map it:\n\n```csharp\nclass Circular { public Circular Self { get; set; } }\n\n// Setup configuration\nvar config = new MapperConfiguration(cfg =\u003e {\n    cfg.CreateMap\u003cCircular, Circular\u003e();\n});\nvar mapper = config.CreateMapper();\n\n// Create a deeply nested object (28,000+ levels)\nvar root = new Circular();\nvar current = root;\nfor (int i = 0; i \u003c 30000; i++) {\n    current.Self = new Circular();\n    current = current.Self;\n}\n\n// This call triggers the StackOverflowException and crashes the process\nmapper.Map\u003cCircular\u003e(root);\n\n```\n\n### Recommended Mitigation\n\n1. **Secure Defaults:** Implement a default `MaxDepth` (e.g., 32 or 64) for all mapping operations.\n2. **Configurable Limit:** Allow users to increase this limit if necessary, but ensure it is enabled by default to protect unsuspecting developers.",
  "id": "GHSA-rvv3-g6hj-g44x",
  "modified": "2026-03-25T18:53:07Z",
  "published": "2026-03-13T20:57:07Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper/security/advisories/GHSA-rvv3-g6hj-g44x"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32933"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper/commit/0afaf1e91648fca1a57512e94dd00a76ee016816"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper/discussions/4624"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper/releases/tag/v15.1.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/LuckyPennySoftware/AutoMapper/releases/tag/v16.1.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "AutoMapper Vulnerable to Denial of Service (DoS) via Uncontrolled Recursion"
}


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  • 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.
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  • 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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