CWE-434
AllowedUnrestricted Upload of File with Dangerous Type
Abstraction: Base · Status: Draft
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
6003 vulnerabilities reference this CWE, most recent first.
GHSA-59H8-P88C-WM46
Vulnerability from github – Published: 2025-08-21 21:32 – Updated: 2025-08-21 21:32An attacker could exploit this vulnerability by uploading arbitrary files via a specific service, which could lead to system compromise.
{
"affected": [],
"aliases": [
"CVE-2025-24489"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-21T20:15:31Z",
"severity": "MODERATE"
},
"details": "An attacker could exploit this vulnerability by uploading arbitrary \nfiles via a specific service, which could lead to system compromise.",
"id": "GHSA-59h8-p88c-wm46",
"modified": "2025-08-21T21:32:06Z",
"published": "2025-08-21T21:32:06Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-24489"
},
{
"type": "WEB",
"url": "https://www.cisa.gov/news-events/ics-medical-advisories/icsma-25-100-01"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-59HM-M98H-48VJ
Vulnerability from github – Published: 2022-05-14 02:01 – Updated: 2022-05-14 02:01Umbraco before 7.2.0 has a remote PHP code execution vulnerability because Umbraco.Web.UI/config/umbracoSettings.Release.config does not block the upload of .php files.
{
"affected": [],
"aliases": [
"CVE-2014-10074"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-08-27T04:29:00Z",
"severity": "CRITICAL"
},
"details": "Umbraco before 7.2.0 has a remote PHP code execution vulnerability because Umbraco.Web.UI/config/umbracoSettings.Release.config does not block the upload of .php files.",
"id": "GHSA-59hm-m98h-48vj",
"modified": "2022-05-14T02:01:47Z",
"published": "2022-05-14T02:01:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2014-10074"
},
{
"type": "WEB",
"url": "https://github.com/Umbraco/Umbraco-CMS/commit/cad06502235acabf7fb7dca779d2f78f08547e39"
},
{
"type": "WEB",
"url": "http://issues.umbraco.org/issue/U4-5901"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-59JW-JQF4-3WQ3
Vulnerability from github – Published: 2021-03-22 23:28 – Updated: 2022-02-08 21:33Impact
The vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types.
Patches
If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.
Workarounds
See workarounds for the different versions covering all CVEs.
References
See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for CVE-2021-21344.
Credits
钟潦贵 (Liaogui Zhong) found and reported the issue to XStream and provided the required information to reproduce it.
For more information
If you have any questions or comments about this advisory: * Open an issue in XStream * Contact us at XStream Google Group
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "com.thoughtworks.xstream:xstream"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.16"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-21344"
],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-502"
],
"github_reviewed": true,
"github_reviewed_at": "2021-03-22T23:23:49Z",
"nvd_published_at": "2021-03-23T00:15:00Z",
"severity": "MODERATE"
},
"details": "### Impact\nThe vulnerability may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. No user is affected, who followed the recommendation to setup XStream\u0027s security framework with a whitelist limited to the minimal required types.\n\n### Patches\nIf you rely on XStream\u0027s default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.16.\n\n### Workarounds\nSee [workarounds](https://x-stream.github.io/security.html#workaround) for the different versions covering all CVEs.\n\n### References\nSee full information about the nature of the vulnerability and the steps to reproduce it in XStream\u0027s documentation for [CVE-2021-21344](https://x-stream.github.io/CVE-2021-21344.html).\n\n### Credits\n\u949f\u6f66\u8d35 (Liaogui Zhong) found and reported the issue to XStream and provided the required information to reproduce it.\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [XStream](https://github.com/x-stream/xstream/issues)\n* Contact us at [XStream Google Group](https://groups.google.com/group/xstream-user)",
"id": "GHSA-59jw-jqf4-3wq3",
"modified": "2022-02-08T21:33:08Z",
"published": "2021-03-22T23:28:23Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/x-stream/xstream/security/advisories/GHSA-59jw-jqf4-3wq3"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21344"
},
{
"type": "PACKAGE",
"url": "https://github.com/x-stream/xstream"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd@%3Cusers.activemq.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0@%3Cdev.jmeter.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20210430-0002"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2021/dsa-5004"
},
{
"type": "WEB",
"url": "https://www.oracle.com//security-alerts/cpujul2021.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpujan2022.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuoct2021.html"
},
{
"type": "WEB",
"url": "https://x-stream.github.io/CVE-2021-21344.html"
},
{
"type": "WEB",
"url": "https://x-stream.github.io/security.html#workaround"
},
{
"type": "WEB",
"url": "http://x-stream.github.io/changes.html#1.4.16"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "XStream is vulnerable to an Arbitrary Code Execution attack"
}
GHSA-59RV-395V-G9XW
Vulnerability from github – Published: 2023-02-21 21:30 – Updated: 2023-02-27 18:32A vulnerability, which was classified as problematic, has been found in SourceCodester Best POS Management System 1.0. This issue affects some unknown processing of the file index.php?page=site_settings of the component Image Handler. The manipulation leads to unrestricted upload. The attack may be initiated remotely. The associated identifier of this vulnerability is VDB-221591.
{
"affected": [],
"aliases": [
"CVE-2023-0943"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-02-21T20:15:00Z",
"severity": "HIGH"
},
"details": "A vulnerability, which was classified as problematic, has been found in SourceCodester Best POS Management System 1.0. This issue affects some unknown processing of the file index.php?page=site_settings of the component Image Handler. The manipulation leads to unrestricted upload. The attack may be initiated remotely. The associated identifier of this vulnerability is VDB-221591.",
"id": "GHSA-59rv-395v-g9xw",
"modified": "2023-02-27T18:32:03Z",
"published": "2023-02-21T21:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-0943"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.221591"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.221591"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-59VC-4MM8-J289
Vulnerability from github – Published: 2026-02-21 00:31 – Updated: 2026-02-21 00:31Chamilo LMS 1.11.8 contains an arbitrary file upload vulnerability that allows authenticated users to upload and execute PHP files through the elfinder filemanager module. Attackers can upload files with image headers in the social myfiles section, rename them to PHP extensions, and execute arbitrary code by accessing the uploaded files.
{
"affected": [],
"aliases": [
"CVE-2018-25158"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-20T23:15:59Z",
"severity": "HIGH"
},
"details": "Chamilo LMS 1.11.8 contains an arbitrary file upload vulnerability that allows authenticated users to upload and execute PHP files through the elfinder filemanager module. Attackers can upload files with image headers in the social myfiles section, rename them to PHP extensions, and execute arbitrary code by accessing the uploaded files.",
"id": "GHSA-59vc-4mm8-j289",
"modified": "2026-02-21T00:31:42Z",
"published": "2026-02-21T00:31:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-25158"
},
{
"type": "WEB",
"url": "https://github.com/chamilo/chamilo-lms"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/47423"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/chamilo-lms-arbitrary-file-upload-via-elfinder"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-59VV-G2MQ-64C5
Vulnerability from github – Published: 2022-05-24 17:36 – Updated: 2022-05-24 17:36An arbitrary code execution vulnerability in Kyland KPS2204 6 Port Managed Din-Rail Programmable Serial Device Servers Software Version:R0002.P05 allows remote attackers to upload a malicious script file by constructing a POST type request and writing a payload in the request parameters as an instruction to write a file.
{
"affected": [],
"aliases": [
"CVE-2020-25010"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2020-12-17T04:15:00Z",
"severity": "CRITICAL"
},
"details": "An arbitrary code execution vulnerability in Kyland KPS2204 6 Port Managed Din-Rail Programmable Serial Device Servers Software Version:R0002.P05 allows remote attackers to upload a malicious script file by constructing a POST type request and writing a payload in the request parameters as an instruction to write a file.",
"id": "GHSA-59vv-g2mq-64c5",
"modified": "2022-05-24T17:36:44Z",
"published": "2022-05-24T17:36:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-25010"
},
{
"type": "WEB",
"url": "https://github.com/AnfieldQi/CVE_list/blob/master/CVE-2020-25010.md"
},
{
"type": "WEB",
"url": "https://www.cnvd.org.cn/flaw/show/CNVD-2020-55990"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-59XG-4F7F-395P
Vulnerability from github – Published: 2024-01-26 18:30 – Updated: 2024-01-26 18:30A vulnerability was found in Niushop B2B2C V5 and classified as critical. Affected by this issue is some unknown functionality of the file \app\model\Upload.php. The manipulation leads to unrestricted upload. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-252140. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
{
"affected": [],
"aliases": [
"CVE-2024-0933"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-01-26T17:15:11Z",
"severity": "MODERATE"
},
"details": "A vulnerability was found in Niushop B2B2C V5 and classified as critical. Affected by this issue is some unknown functionality of the file \\app\\model\\Upload.php. The manipulation leads to unrestricted upload. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-252140. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.",
"id": "GHSA-59xg-4f7f-395p",
"modified": "2024-01-26T18:30:34Z",
"published": "2024-01-26T18:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-0933"
},
{
"type": "WEB",
"url": "https://docs.qq.com/doc/DYnNWeHdTVXZqZURH"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.252140"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.252140"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-5C2H-V384-QMPW
Vulnerability from github – Published: 2023-01-03 21:30 – Updated: 2023-01-10 18:30RESERVED There is an arbitrary file upload vulnerability in b2evolution v7.2.5. Attackers can use this vulnerability to execute remote commands.
{
"affected": [],
"aliases": [
"CVE-2022-44036"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-01-03T21:15:00Z",
"severity": "HIGH"
},
"details": "RESERVED There is an arbitrary file upload vulnerability in b2evolution v7.2.5. Attackers can use this vulnerability to execute remote commands.",
"id": "GHSA-5c2h-v384-qmpw",
"modified": "2023-01-10T18:30:28Z",
"published": "2023-01-03T21:30:19Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-44036"
},
{
"type": "WEB",
"url": "https://github.com/b2evolution/b2evolution/issues/121"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-5C49-P8M3-FJH3
Vulnerability from github – Published: 2026-04-22 21:31 – Updated: 2026-04-22 21:31The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
{
"affected": [],
"aliases": [
"CVE-2026-1555"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-15T04:17:33Z",
"severity": "CRITICAL"
},
"details": "The WebStack theme for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the io_img_upload() function in all versions up to, and including, 1.2024. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site\u0027s server which may make remote code execution possible.",
"id": "GHSA-5c49-p8m3-fjh3",
"modified": "2026-04-22T21:31:44Z",
"published": "2026-04-22T21:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-1555"
},
{
"type": "WEB",
"url": "https://github.com/owen0o0/WebStack/blob/master/inc/ajax.php#L5"
},
{
"type": "WEB",
"url": "https://github.com/owen0o0/WebStack/tree/master"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/b97805de-1b47-4c9f-baae-2e37c1b78570?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-5C4G-2G7F-VP3X
Vulnerability from github – Published: 2026-01-15 18:31 – Updated: 2026-01-15 18:31File upload vulnerability in Omnispace Agora Project before 25.10 allowing authenticated, or under certain conditions also guest users, via the UploadTmpFile action.
{
"affected": [],
"aliases": [
"CVE-2025-67077"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-01-15T16:16:11Z",
"severity": "MODERATE"
},
"details": "File upload vulnerability in Omnispace Agora Project before 25.10 allowing authenticated, or under certain conditions also guest users, via the UploadTmpFile action.",
"id": "GHSA-5c4g-2g7f-vp3x",
"modified": "2026-01-15T18:31:32Z",
"published": "2026-01-15T18:31:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-67077"
},
{
"type": "WEB",
"url": "https://www.agora-project.net"
},
{
"type": "WEB",
"url": "https://www.helx.io/blog/advisory-agora-project"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation
Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.[REF-422] [REF-423]
Mitigation MIT-21
Strategy: Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
Mitigation
Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically. [REF-423]
Mitigation MIT-5
Strategy: Input Validation
- Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- For example, limiting filenames to alphanumeric characters can help to restrict the introduction of unintended file extensions.
Mitigation
Define a very limited set of allowable extensions and only generate filenames that end in these extensions. Consider the possibility of XSS (CWE-79) before allowing .html or .htm file types.
Mitigation
Strategy: Input Validation
Ensure that only one extension is used in the filename. Some web servers, including some versions of Apache, may process files based on inner extensions so that "filename.php.gif" is fed to the PHP interpreter.[REF-422] [REF-423]
Mitigation
When running on a web server that supports case-insensitive filenames, perform case-insensitive evaluations of the extensions that are provided.
Mitigation MIT-15
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Mitigation
Do not rely exclusively on sanity checks of file contents to ensure that the file is of the expected type and size. It may be possible for an attacker to hide code in some file segments that will still be executed by the server. For example, GIF images may contain a free-form comments field.
Mitigation
Do not rely exclusively on the MIME content type or filename attribute when determining how to render a file. Validating the MIME content type and ensuring that it matches the extension is only a partial solution.
Mitigation MIT-17
Strategy: Environment Hardening
Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
Mitigation MIT-22
Strategy: Sandbox or Jail
- Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
- OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs
In applications, particularly web applications, access to functionality is mitigated by an authorization framework. This framework maps Access Control Lists (ACLs) to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application, or can run queries for data that they otherwise not supposed to.