CWE-73
AllowedExternal Control of File Name or Path
Abstraction: Base · Status: Draft
The product allows user input to control or influence paths or file names that are used in filesystem operations.
1182 vulnerabilities reference this CWE, most recent first.
GHSA-FC5X-R66H-VP5F
Vulnerability from github – Published: 2026-07-22 12:32 – Updated: 2026-07-22 12:32The servereye client (also known as sensorhub, technically ClientAgentContainerService) versions 20.15 and earlier are vulnerable to Local Privilege Escalation. The high-privileged service SE3Recovery (EmergencyRecoveryService.exe), running as SYSTEM, periodically monitors the directory %ProgramData%\ServerEye3\update\ for a trigger file named "update_available". Due to insufficient access restrictions on this directory, a local standard user can create the trigger file and provide a path to a directory containing malicious JSON instructions. The service subsequently executes the utility UpdaterAction.exe with SYSTEM privileges, which parses the instructions and performs an unvalidated file copy from a user-controlled source to a protected system destination (e.g., overwriting a service binary). This leads to full system compromise as the service automatically restarts the overwritten binary with SYSTEM privileges.
{
"affected": [],
"aliases": [
"CVE-2026-14551"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-22T10:17:13Z",
"severity": "HIGH"
},
"details": "The servereye client (also known as sensorhub, technically ClientAgentContainerService) versions 20.15 and earlier are vulnerable to Local Privilege Escalation. The high-privileged service SE3Recovery (EmergencyRecoveryService.exe), running as SYSTEM, periodically monitors the directory %ProgramData%\\ServerEye3\\update\\ for a trigger file named \"update_available\". Due to insufficient access restrictions on this directory, a local standard user can create the trigger file and provide a path to a directory containing malicious JSON instructions. The service subsequently\u00a0executes the utility UpdaterAction.exe with SYSTEM privileges, which parses the instructions and performs an unvalidated file copy from a user-controlled source to a protected system destination (e.g., overwriting a service binary). This leads to full system compromise as the service automatically restarts the overwritten binary with SYSTEM privileges.",
"id": "GHSA-fc5x-r66h-vp5f",
"modified": "2026-07-22T12:32:15Z",
"published": "2026-07-22T12:32:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-14551"
},
{
"type": "WEB",
"url": "https://www.servereye.de/security-bulletins/2026-001"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-FGC5-6VQG-25Q8
Vulnerability from github – Published: 2025-01-30 15:31 – Updated: 2025-01-30 15:31The W2S – Migrate WooCommerce to Shopify plugin for WordPress is vulnerable to Arbitrary File Read in all versions up to, and including, 1.2.1 via the 'viw2s_view_log' AJAX action. This makes it possible for authenticated attackers, with Subscriber-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information.
{
"affected": [],
"aliases": [
"CVE-2024-12861"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-01-30T14:15:33Z",
"severity": "MODERATE"
},
"details": "The W2S \u2013 Migrate WooCommerce to Shopify plugin for WordPress is vulnerable to Arbitrary File Read in all versions up to, and including, 1.2.1 via the \u0027viw2s_view_log\u0027 AJAX action. This makes it possible for authenticated attackers, with Subscriber-level access and above, to read the contents of arbitrary files on the server, which can contain sensitive information.",
"id": "GHSA-fgc5-6vqg-25q8",
"modified": "2025-01-30T15:31:38Z",
"published": "2025-01-30T15:31:38Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-12861"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026old=3227799%40w2s-migrate-woo-to-shopify\u0026new=3227799%40w2s-migrate-woo-to-shopify\u0026sfp_email=\u0026sfph_mail="
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/8a8eeae9-572c-420a-be7d-a240c54e96ae?source=cve"
}
],
"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"
}
]
}
GHSA-FGXV-26Q5-6XQ2
Vulnerability from github – Published: 2026-03-31 18:31 – Updated: 2026-04-01 21:30An arbitrary file overwrite vulnerability in UXGROUP LLC Voice Recorder v10.0 allows attackers to overwrite critical internal files via the file import process, leading to arbitrary code execution or information exposure.
{
"affected": [],
"aliases": [
"CVE-2026-30284"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-31T16:16:29Z",
"severity": "HIGH"
},
"details": "An arbitrary file overwrite vulnerability in UXGROUP LLC Voice Recorder v10.0 allows attackers to overwrite critical internal files via the file import process, leading to arbitrary code execution or information exposure.",
"id": "GHSA-fgxv-26q5-6xq2",
"modified": "2026-04-01T21:30:27Z",
"published": "2026-03-31T18:31:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30284"
},
{
"type": "WEB",
"url": "https://github.com/Secsys-FDU/AF_CVEs/issues/25"
},
{
"type": "WEB",
"url": "https://appcraze.co"
},
{
"type": "WEB",
"url": "https://secsys.fudan.edu.cn"
},
{
"type": "WEB",
"url": "http://voice.com"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-FH6W-C9CF-Q94H
Vulnerability from github – Published: 2025-10-14 18:30 – Updated: 2025-10-14 18:30External control of file name or path in Confidential Azure Container Instances allows an authorized attacker to elevate privileges locally.
{
"affected": [],
"aliases": [
"CVE-2025-59292"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-14T17:16:12Z",
"severity": "HIGH"
},
"details": "External control of file name or path in Confidential Azure Container Instances allows an authorized attacker to elevate privileges locally.",
"id": "GHSA-fh6w-c9cf-q94h",
"modified": "2025-10-14T18:30:36Z",
"published": "2025-10-14T18:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-59292"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59292"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-FHQM-96V7-CXMF
Vulnerability from github – Published: 2026-09-14 15:32 – Updated: 2026-09-14 15:32LaraDashboard versions 0.9.2 through 1.2.2 contain a path traversal vulnerability in the core-upgrade backup handling. CoreUpgradeController and BackupService (e.g. BackupService::deleteBackup()) concatenate the user-supplied backup_file/filename value directly onto the backup directory path without normalisation, without applying basename(), and without verifying that the resolved path remains inside storage/app/core-backups; the corresponding form requests only validate the value as a bounded string. An authenticated user holding only the delegated settings.edit permission (not Superadmin) can supply ../ traversal sequences to delete arbitrary files reachable on the host filesystem, including outside the application tree, or to restore a ZIP archive from an arbitrary on-disk location, writing arbitrary files into the application directories and achieving remote code execution. Note: the advisory states the vulnerable concatenation was introduced in the v0.9.7 release line. No patched version was available at the time of publication.
{
"affected": [],
"aliases": [
"CVE-2026-90932"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-14T13:19:31Z",
"severity": "HIGH"
},
"details": "LaraDashboard versions 0.9.2 through 1.2.2 contain a path traversal vulnerability in the core-upgrade backup handling. CoreUpgradeController and BackupService (e.g. BackupService::deleteBackup()) concatenate the user-supplied backup_file/filename value directly onto the backup directory path without normalisation, without applying basename(), and without verifying that the resolved path remains inside storage/app/core-backups; the corresponding form requests only validate the value as a bounded string. An authenticated user holding only the delegated settings.edit permission (not Superadmin) can supply ../ traversal sequences to delete arbitrary files reachable on the host filesystem, including outside the application tree, or to restore a ZIP archive from an arbitrary on-disk location, writing arbitrary files into the application directories and achieving remote code execution. Note: the advisory states the vulnerable concatenation was introduced in the v0.9.7 release line. No patched version was available at the time of publication.",
"id": "GHSA-fhqm-96v7-cxmf",
"modified": "2026-09-14T15:32:45Z",
"published": "2026-09-14T15:32:44Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/laradashboard/laradashboard/security/advisories/GHSA-g48h-h5pc-396j"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90932"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/laradashboard-0.9.2-through-1.2.2-path-traversal-rce"
}
],
"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"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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-FJM7-6RV9-337H
Vulnerability from github – Published: 2026-02-19 18:31 – Updated: 2026-02-19 18:31Dell Unisphere for PowerMax, version(s) 10.2, contain(s) an External Control of File Name or Path vulnerability. A low privileged attacker with remote access could potentially exploit this vulnerability to delete arbitrary files.
{
"affected": [],
"aliases": [
"CVE-2026-26360"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-19T09:16:25Z",
"severity": "HIGH"
},
"details": "Dell Unisphere for PowerMax, version(s) 10.2, contain(s) an External Control of File Name or Path vulnerability. A low privileged attacker with remote access could potentially exploit this vulnerability to delete arbitrary files.",
"id": "GHSA-fjm7-6rv9-337h",
"modified": "2026-02-19T18:31:53Z",
"published": "2026-02-19T18:31:53Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26360"
},
{
"type": "WEB",
"url": "https://www.dell.com/support/kbdoc/en-us/000429268/dsa-2026-102-dell-unisphere-for-powermax-and-powermax-eem-security-update-for-multiple-vulnerabilities"
}
],
"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:H",
"type": "CVSS_V3"
}
]
}
GHSA-FP5J-Q9FH-M8QX
Vulnerability from github – Published: 2025-02-27 15:31 – Updated: 2025-02-27 15:31HkCms v2.3.2.240702 was discovered to contain an arbitrary file write vulnerability in the component Appcenter.php.
{
"affected": [],
"aliases": [
"CVE-2025-25761"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-27T15:15:41Z",
"severity": "HIGH"
},
"details": "HkCms v2.3.2.240702 was discovered to contain an arbitrary file write vulnerability in the component Appcenter.php.",
"id": "GHSA-fp5j-q9fh-m8qx",
"modified": "2025-02-27T15:31:52Z",
"published": "2025-02-27T15:31:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-25761"
},
{
"type": "WEB",
"url": "https://github.com/147536951/Qianyi-learn/blob/main/Hkcms.pdf"
}
],
"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-FPP4-775Q-MQRM
Vulnerability from github – Published: 2026-01-13 18:31 – Updated: 2026-03-27 21:31External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing over a network.
{
"affected": [],
"aliases": [
"CVE-2026-20872"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-01-13T18:16:16Z",
"severity": "MODERATE"
},
"details": "External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing over a network.",
"id": "GHSA-fpp4-775q-mqrm",
"modified": "2026-03-27T21:31:32Z",
"published": "2026-01-13T18:31:09Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20872"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20872"
},
{
"type": "WEB",
"url": "https://www.vicarius.io/vsociety/posts/cve-2026-20872-detection-script-spoofing-vulnerability-in-windows-ntlm"
},
{
"type": "WEB",
"url": "https://www.vicarius.io/vsociety/posts/cve-2026-20872-mitigation-script-spoofing-vulnerability-in-windows-ntlm"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-FPVX-GW57-2P3V
Vulnerability from github – Published: 2024-05-15 18:30 – Updated: 2024-05-15 18:30A vulnerability in the Tail-f High Availability Cluster Communications (HCC) function pack of Cisco Crosswork Network Services Orchestrator (NSO) could allow an authenticated, local attacker to elevate privileges to root on an affected device.
This vulnerability exists because a user-controlled search path is used to locate executable files. An attacker could exploit this vulnerability by configuring the application in a way that causes a malicious file to be executed. A successful exploit could allow the attacker to execute arbitrary code on an affected device as the root user. To exploit this vulnerability, the attacker would need valid credentials on an affected device.
{
"affected": [],
"aliases": [
"CVE-2024-20366"
],
"database_specific": {
"cwe_ids": [
"CWE-427",
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-15T18:15:09Z",
"severity": "HIGH"
},
"details": "A vulnerability in the Tail-f High Availability Cluster Communications (HCC) function pack of Cisco Crosswork Network Services Orchestrator (NSO) could allow an authenticated, local attacker to elevate privileges to root on an affected device.\n\n This vulnerability exists because a user-controlled search path is used to locate executable files. An attacker could exploit this vulnerability by configuring the application in a way that causes a malicious file to be executed. A successful exploit could allow the attacker to execute arbitrary code on an affected device as the root user. To exploit this vulnerability, the attacker would need valid credentials on an affected device.",
"id": "GHSA-fpvx-gw57-2p3v",
"modified": "2024-05-15T18:30:35Z",
"published": "2024-05-15T18:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-20366"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nso-hcc-priv-esc-OWBWCs5D"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-FQXF-49HH-94MJ
Vulnerability from github – Published: 2025-04-16 21:30 – Updated: 2025-04-17 15:32Wallos <=2.38.2 has a file upload vulnerability in the restore database function, which allows unauthenticated users to restore database by uploading a ZIP file. The contents of the ZIP file are extracted on the server. This functionality enables an unauthenticated attacker to upload malicious files to the server. Once a web shell is installed, the attacker gains the ability to execute arbitrary commands.
{
"affected": [],
"aliases": [
"CVE-2024-55372"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-16T21:15:45Z",
"severity": "CRITICAL"
},
"details": "Wallos \u003c=2.38.2 has a file upload vulnerability in the restore database function, which allows unauthenticated users to restore database by uploading a ZIP file. The contents of the ZIP file are extracted on the server. This functionality enables an unauthenticated attacker to upload malicious files to the server. Once a web shell is installed, the attacker gains the ability to execute arbitrary commands.",
"id": "GHSA-fqxf-49hh-94mj",
"modified": "2025-04-17T15:32:34Z",
"published": "2025-04-16T21:30:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-55372"
},
{
"type": "WEB",
"url": "https://www.datafarm.co.th/blog/CVE-2024-55371-and-CVE-2024-55372-Malicious-File-Upload-to-RCE-in-Wallos-Application"
}
],
"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"
}
]
}
Mitigation
When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap provide this capability.
Mitigation
- Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory.
- Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation
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 MIT-5.1
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.
- When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434.
- Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.
Mitigation
Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59).
Mitigation
Use OS-level permissions and run as a low-privileged user to limit the scope of any successful attack.
Mitigation
If you are using PHP, configure your application so that it does not use register_globals. During implementation, develop your application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
Mitigation
Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.
CAPEC-13: Subverting Environment Variable Values
The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.
CAPEC-267: Leverage Alternate Encoding
An adversary leverages the possibility to encode potentially harmful input or content used by applications such that the applications are ineffective at validating this encoding standard.
CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic
This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple ways of encoding a URL and abuse the interpretation of the URL. A URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
CAPEC-72: URL Encoding
This attack targets the encoding of the URL. An adversary can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL.
CAPEC-76: Manipulating Web Input to File System Calls
An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
CAPEC-78: Using Escaped Slashes in Alternate Encoding
This attack targets the use of the backslash in alternate encoding. An adversary can provide a backslash as a leading character and causes a parser to believe that the next character is special. This is called an escape. By using that trick, the adversary tries to exploit alternate ways to encode the same character which leads to filter problems and opens avenues to attack.
CAPEC-79: Using Slashes in Alternate Encoding
This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.
CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic
This attack is a specific variation on leveraging alternate encodings to bypass validation logic. This attack leverages the possibility to encode potentially harmful input in UTF-8 and submit it to applications not expecting or effective at validating this encoding standard making input filtering difficult. UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. Legal UTF-8 characters are one to four bytes long. However, early version of the UTF-8 specification got some entries wrong (in some cases it permitted overlong characters). UTF-8 encoders are supposed to use the "shortest possible" encoding, but naive decoders may accept encodings that are longer than necessary. According to the RFC 3629, a particularly subtle form of this attack can be carried out against a parser which performs security-critical validity checks against the UTF-8 encoded form of its input, but interprets certain illegal octet sequences as characters.