Common Weakness Enumeration

CWE-400

Discouraged

Uncontrolled Resource Consumption

Abstraction: Class · Status: Draft

The product does not properly control the allocation and maintenance of a limited resource.

5412 vulnerabilities reference this CWE, most recent first.

GHSA-X62Q-P736-3997

Vulnerability from github – Published: 2025-12-02 00:36 – Updated: 2025-12-02 00:36
VLAI
Summary
Grav is vulnerable to a DOS on the admin panel
Details

DOS on the admin panel

Severity Rating: Medium

Vector: Denial Of Service

CVE: XXX

CWE: 400 - Uncontrolled Resource Consumption

CVSS Score: 4.9

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Analysis

A Denial of Service (DoS) vulnerability has been identified in the application related to the handling of scheduled_at parameters. Specifically, the application fails to properly sanitize input for cron expressions. By manipulating the scheduled_at parameter with a malicious input, such as a single quote, the application admin panel becomes non-functional, causing significant disruptions to administrative operations.

The only way to recover from this issue is to manually access the host server and modify the backup.yaml file to correct the corrupted cron expression

Proof of Concept

1) Change the value of scheduled_at parameter to ' as shown in the following figures at the http://127.0.0.1/admin/tools endpoint, and observe the response in the second figure: gravdos2 Figure: Http request on tool endpoint gravdos3 Figure: Http response on tool endpoint

2) When trying to access the admin panel, the panel is broken as shown in the following figure. Additionally, the value change is reflected in the backup.yaml file, as shown in the second figure: gravdos4 Figure: Error message view gravdos5 Figure: Backup.yaml file

Workarounds

No workaround is currently known

Timeline

2024-07-24 Issue identified

2024-09-27 Vendor contacted

About X41 D-Sec GmbH

X41 is an expert provider for application security services. Having extensive industry experience and expertise in the area of information security, a strong core security team of world class security experts enables X41 to perform premium security services.

Fields of expertise in the area of application security are security centered code reviews, binary reverse engineering and vulnerability discovery. Custom research and IT security consulting and support services are core competencies of X41.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "getgrav/grav"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.8.0-beta.27"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-66303"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-12-02T00:36:59Z",
    "nvd_published_at": "2025-12-01T22:15:49Z",
    "severity": "MODERATE"
  },
  "details": "# DOS on the admin panel\n**Severity Rating:** Medium \n\n**Vector:** Denial Of Service\n\n**CVE:** XXX\n\n**CWE:** 400 - Uncontrolled Resource Consumption\n\n**CVSS Score:** 4.9\n\n**CVSS Vector:** CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H\n\n## Analysis\n\nA Denial of Service (DoS) vulnerability has been identified in the application related to the handling of `scheduled_at` parameters. Specifically, the application fails to properly sanitize input for cron expressions. By manipulating the `scheduled_at` parameter with a malicious input, such as a single quote, the application admin panel becomes non-functional, causing significant disruptions to administrative operations.\n\nThe only way to recover from this issue is to manually access the host server and modify the `backup.yaml` file to correct the corrupted cron expression\n\n## Proof of Concept\n\n1) Change the value of `scheduled_at` parameter to `\u0027` as shown in the following figures at the `http://127.0.0.1/admin/tools` endpoint, and observe the response in the second figure:\n  ![gravdos2](https://github.com/user-attachments/assets/b2d8935f-c8ba-4eda-998a-8a20b3d5ef7c)\n  *Figure: Http request on tool endpoint*\n![gravdos3](https://github.com/user-attachments/assets/2a283254-316a-45b3-a5ac-6804e2494cd7)\n  *Figure: Http response on tool endpoint*\n\n2) When trying to access the admin panel, the panel is broken as shown in the following figure. Additionally, the value change is reflected in the `backup.yaml` file, as shown in the second figure:\n  ![gravdos4](https://github.com/user-attachments/assets/1257adcb-96c4-4b30-864e-9aa01e410ded)\n  *Figure: Error message view*\n![gravdos5](https://github.com/user-attachments/assets/4cef7c49-6a1e-4414-8332-3195aa2dfc77)\n  *Figure: Backup.yaml file*\n\n\n## Workarounds\nNo workaround is currently known\n\n# Timeline\n**2024-07-24** Issue identified\n\n**2024-09-27** Vendor contacted\n\n\n# About X41 D-Sec GmbH\nX41 is an expert provider for application security services.\nHaving extensive industry experience and expertise in the area of information\nsecurity, a strong core security team of world class security experts enables\nX41 to perform premium security services.\n\nFields of expertise in the area of application security are security centered\ncode reviews, binary reverse engineering and vulnerability discovery.\nCustom research and IT security consulting and support services are core\ncompetencies of X41.",
  "id": "GHSA-x62q-p736-3997",
  "modified": "2025-12-02T00:36:59Z",
  "published": "2025-12-02T00:36:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/getgrav/grav/security/advisories/GHSA-x62q-p736-3997"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66303"
    },
    {
      "type": "WEB",
      "url": "https://github.com/getgrav/grav/commit/9d11094e4133f059688fad1e00dbe96fb6e3ead7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/getgrav/grav"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Grav is vulnerable to a DOS on the admin panel"
}

GHSA-X67R-8JFC-3R5M

Vulnerability from github – Published: 2023-10-04 18:30 – Updated: 2024-01-25 18:30
VLAI
Details

A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device.

This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2023-20259"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-10-04T17:15:09Z",
    "severity": "HIGH"
  },
  "details": "A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device.\n\n This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.",
  "id": "GHSA-x67r-8jfc-3r5m",
  "modified": "2024-01-25T18:30:44Z",
  "published": "2023-10-04T18:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-20259"
    },
    {
      "type": "WEB",
      "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-apidos-PGsDcdNF"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X68F-C227-67VJ

Vulnerability from github – Published: 2022-03-02 00:00 – Updated: 2022-03-17 00:04
VLAI
Details

A security vulnerability in the Spectrum Scale 5.0 and 5.1 allows a non-root user to overflow the mmfsd daemon with requests and preventing the daemon to service other requests. IBM X-Force ID: 191599.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2020-4925"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2022-03-01T17:15:00Z",
    "severity": "MODERATE"
  },
  "details": "A security vulnerability in the Spectrum Scale 5.0 and 5.1 allows a non-root user to overflow the mmfsd daemon with requests and preventing the daemon to service other requests. IBM X-Force ID: 191599.",
  "id": "GHSA-x68f-c227-67vj",
  "modified": "2022-03-17T00:04:28Z",
  "published": "2022-03-02T00:00:19Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-4925"
    },
    {
      "type": "WEB",
      "url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/191599"
    },
    {
      "type": "WEB",
      "url": "https://www.ibm.com/support/pages/node/6560094"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X6FG-PGP3-2G2V

Vulnerability from github – Published: 2022-05-24 19:05 – Updated: 2022-05-24 19:05
VLAI
Details

An issue was discovered on 4GEE ROUTER HH70VB Version HH70_E1_02.00_22. Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted. Then the web server is denial-of-service.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2021-33822"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2021-06-18T19:15:00Z",
    "severity": "HIGH"
  },
  "details": "An issue was discovered on 4GEE ROUTER HH70VB Version HH70_E1_02.00_22. Attackers can use slowhttptest tool to send incomplete HTTP request, which could make server keep waiting for the packet to finish the connection, until its resource exhausted. Then the web server is denial-of-service.",
  "id": "GHSA-x6fg-pgp3-2g2v",
  "modified": "2022-05-24T19:05:39Z",
  "published": "2022-05-24T19:05:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-33822"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Jian-Xian/CVE-POC/blob/master/CVE-2021-33822.md"
    },
    {
      "type": "WEB",
      "url": "https://github.com/shekyan/slowhttptest"
    },
    {
      "type": "WEB",
      "url": "https://www.sing4g.com/product-page/4gee-router-hh70vb-4g-300mbps-2lan-32wifi"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

GHSA-X6H4-889M-MH2V

Vulnerability from github – Published: 2022-05-13 01:47 – Updated: 2022-05-13 01:47
VLAI
Details

A userspace process can cause a Denial of Service in the camera driver in all Qualcomm products with Android releases from CAF using the Linux kernel.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2017-8264"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2017-08-11T15:29:00Z",
    "severity": "HIGH"
  },
  "details": "A userspace process can cause a Denial of Service in the camera driver in all Qualcomm products with Android releases from CAF using the Linux kernel.",
  "id": "GHSA-x6h4-889m-mh2v",
  "modified": "2022-05-13T01:47:25Z",
  "published": "2022-05-13T01:47:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2017-8264"
    },
    {
      "type": "WEB",
      "url": "https://source.android.com/security/bulletin/2017-07-01"
    },
    {
      "type": "WEB",
      "url": "http://www.securityfocus.com/bid/99465"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X6JW-W885-QWPC

Vulnerability from github – Published: 2024-03-15 12:30 – Updated: 2024-03-15 12:30
VLAI
Details

Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to limit the number of @-mentions processed per message, allowing an authenticated attacker to crash the client applications of other users via large, crafted messages.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2024-2446"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-03-15T10:15:08Z",
    "severity": "MODERATE"
  },
  "details": "Mattermost versions 8.1.x before 8.1.10, 9.2.x before 9.2.6, 9.3.x before 9.3.2, and 9.4.x before 9.4.3 fail to limit the number of @-mentions processed per message, allowing an authenticated attacker to crash the client applications of other users via large, crafted messages.\n\n",
  "id": "GHSA-x6jw-w885-qwpc",
  "modified": "2024-03-15T12:30:36Z",
  "published": "2024-03-15T12:30:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-2446"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-X6M6-5HRF-FH6R

Vulnerability from github – Published: 2020-09-01 21:26 – Updated: 2023-12-07 22:05
VLAI
Summary
Denial of Service in markdown-it-toc-and-anchor
Details

All versions of markdown-it-toc-and-anchor are vulnerable to Denial of Service. Parsing markdown containing **text**+\n@[toc] causes the application to enter and infinite loop.

Recommendation

No fix is currently available. Consider using an alternative module until a fix is made available.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "markdown-it-toc-and-anchor"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.2.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2020-08-31T18:34:25Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "All versions of `markdown-it-toc-and-anchor` are vulnerable to Denial of Service. Parsing markdown containing `**text**+\\n@[toc]` causes the application to enter and infinite loop.\n\n\n## Recommendation\n\nNo fix is currently available. Consider using an alternative module until a fix is made available.",
  "id": "GHSA-x6m6-5hrf-fh6r",
  "modified": "2023-12-07T22:05:03Z",
  "published": "2020-09-01T21:26:50Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://github.com/medfreeman/markdown-it-toc-and-anchor"
    },
    {
      "type": "WEB",
      "url": "https://snyk.io/vuln/SNYK-JS-MARKDOWNITTOCANDANCHOR-73500"
    },
    {
      "type": "WEB",
      "url": "https://www.npmjs.com/advisories/749"
    }
  ],
  "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": "Denial of Service in markdown-it-toc-and-anchor"
}

GHSA-X6PW-RQMX-W72P

Vulnerability from github – Published: 2023-07-12 15:30 – Updated: 2024-04-04 06:04
VLAI
Details

An issue discovered in MikroTik Router v6.46.3 and earlier allows attacker to cause denial of service via misconfiguration in the SSH daemon.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2020-20021"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-07-12T13:15:09Z",
    "severity": "HIGH"
  },
  "details": "An issue discovered in MikroTik Router v6.46.3 and earlier allows attacker to cause denial of service via misconfiguration in the SSH daemon.",
  "id": "GHSA-x6pw-rqmx-w72p",
  "modified": "2024-04-04T06:04:00Z",
  "published": "2023-07-12T15:30:51Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-20021"
    },
    {
      "type": "WEB",
      "url": "https://www.exploit-db.com/exploits/48228"
    },
    {
      "type": "WEB",
      "url": "http://mikrotik.com"
    },
    {
      "type": "WEB",
      "url": "http://router.com"
    }
  ],
  "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"
    }
  ]
}

GHSA-X6PX-H85M-3M6V

Vulnerability from github – Published: 2023-08-22 21:30 – Updated: 2024-04-04 07:08
VLAI
Details

memcached 1.6.7 allows a Denial of Service via multi-packet uploads in UDP.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2022-48571"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2023-08-22T19:16:32Z",
    "severity": "HIGH"
  },
  "details": "memcached 1.6.7 allows a Denial of Service via multi-packet uploads in UDP.",
  "id": "GHSA-x6px-h85m-3m6v",
  "modified": "2024-04-04T07:08:19Z",
  "published": "2023-08-22T21:30:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-48571"
    },
    {
      "type": "WEB",
      "url": "https://github.com/memcached/memcached/commit/6b319c8c7a29e9c353dec83dc92f01905f6c8966"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2023/09/msg00004.html"
    }
  ],
  "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"
    }
  ]
}

GHSA-X6RX-7HMF-R792

Vulnerability from github – Published: 2022-05-24 17:15 – Updated: 2024-04-04 02:49
VLAI
Details

InstallBuilder AutoUpdate tool and regular installers enabling built with versions earlier than 19.11 are vulnerable to Billion laughs attack (denial-of-service).

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2020-3946"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-776"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2020-04-20T20:15:00Z",
    "severity": "HIGH"
  },
  "details": "InstallBuilder AutoUpdate tool and regular installers enabling \u003ccheckForUpdates\u003e built with versions earlier than 19.11 are vulnerable to Billion laughs attack (denial-of-service).",
  "id": "GHSA-x6rx-7hmf-r792",
  "modified": "2024-04-04T02:49:57Z",
  "published": "2022-05-24T17:15:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-3946"
    },
    {
      "type": "WEB",
      "url": "https://blog.installbuilder.com/2019/12/configure-autoupdate-project-settings.html"
    }
  ],
  "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"
    }
  ]
}

Mitigation
Architecture and Design

Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.

Mitigation
Architecture and Design
  • Mitigation of resource exhaustion attacks requires that the target system either:
  • The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
  • The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
  • recognizes the attack and denies that user further access for a given amount of time, or
  • uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Mitigation
Architecture and Design

Ensure that protocols have specific limits of scale placed on them.

Mitigation
Implementation

Ensure that all failures in resource allocation place the system into a safe posture.

CAPEC-147: XML Ping of the Death

An attacker initiates a resource depletion attack where a large number of small XML messages are delivered at a sufficiently rapid rate to cause a denial of service or crash of the target. Transactions such as repetitive SOAP transactions can deplete resources faster than a simple flooding attack because of the additional resources used by the SOAP protocol and the resources necessary to process SOAP messages. The transactions used are immaterial as long as they cause resource utilization on the target. In other words, this is a normal flooding attack augmented by using messages that will require extra processing on the target.

CAPEC-227: Sustained Client Engagement

An adversary attempts to deny legitimate users access to a resource by continually engaging a specific resource in an attempt to keep the resource tied up as long as possible. The adversary's primary goal is not to crash or flood the target, which would alert defenders; rather it is to repeatedly perform actions or abuse algorithmic flaws such that a given resource is tied up and not available to a legitimate user. By carefully crafting a requests that keep the resource engaged through what is seemingly benign requests, legitimate users are limited or completely denied access to the resource.

CAPEC-492: Regular Expression Exponential Blowup

An adversary may execute an attack on a program that uses a poor Regular Expression(Regex) implementation by choosing input that results in an extreme situation for the Regex. A typical extreme situation operates at exponential time compared to the input size. This is due to most implementations using a Nondeterministic Finite Automaton(NFA) state machine to be built by the Regex algorithm since NFA allows backtracking and thus more complex regular expressions.