CWE-59
AllowedImproper Link Resolution Before File Access ('Link Following')
Abstraction: Base · Status: Draft
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
2433 vulnerabilities reference this CWE, most recent first.
GHSA-WR8V-PMCM-77GW
Vulnerability from github – Published: 2022-05-24 19:05 – Updated: 2022-05-24 19:05It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-15 package apport hooks, it could expose private data to other local users.
{
"affected": [],
"aliases": [
"CVE-2021-32551"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-06-12T04:15:00Z",
"severity": "MODERATE"
},
"details": "It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-15 package apport hooks, it could expose private data to other local users.",
"id": "GHSA-wr8v-pmcm-77gw",
"modified": "2022-05-24T19:05:16Z",
"published": "2022-05-24T19:05:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32551"
},
{
"type": "WEB",
"url": "https://bugs.launchpad.net/ubuntu/+source/apport/+bug/1917904"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WV6G-X823-WX9M
Vulnerability from github – Published: 2026-10-15 18:21 – Updated: 2026-10-15 18:21Summary
Terragrunt's terragrunt catalog command clones each repository referenced in your catalog configuration into a temporary working directory. In affected versions, the clone path it derived was deterministic and sat under the shared system temporary directory, in the form <tmp>/catalog-<base64 sha1 of the repo URL>. Because that path was predictable and Terragrunt followed a symlink already present there instead of rejecting it, a local attacker could plant a symlink at that path and cause Terragrunt to delete a directory and re-clone into it outside the intended temporary root.
Impact
This affected users who ran terragrunt catalog on a host they shared with other local users or processes they did not fully trust, such as a multi-user server or a shared CI runner. The attack required a local attacker: a separate local user or process able to write to the shared system temporary directory. It was not remotely exploitable, and the victim had to run terragrunt catalog while the attacker's symlink was already in place.
Because the predictable path depended only on the repository URL being cataloged and the location of the system temporary directory, the attacker could compute it in advance and plant a symlink there before the victim ran the command. When the victim ran terragrunt catalog, Terragrunt followed the symlink out of the intended temporary root, deleted an existing <repoName> directory under the attacker-chosen parent, and repopulated that path with the cloned repository contents. All of this happened in the security context of the user running Terragrunt.
The attacker controlled the parent directory the symlink pointed to, but not the leaf name: the leaf was fixed to <repoName>, derived from the repository URL the victim cataloged. The primitive was deletion of an existing <repoName> directory outside the temporary root, followed by a re-clone into that same path. On a single-user machine with no hostile local processes, exposure was minimal.
Affected Versions
- Terragrunt
< v1.1.1
Patches
This vulnerability has been resolved in Terragrunt version v1.1.1.
All users are strongly advised to upgrade.
Workarounds
If you cannot upgrade immediately, ensure that you do not allow untrusted parties to control the values of TMPDIR, TMP, and TEMP in environments where you run terragrunt catalog.
Technical Details
When you run terragrunt catalog, the catalog service iterates over the repositories in your configuration and prepares a local clone of each one. In affected versions, for a given repository URL it built a clone path by hashing the URL and joining the result under the shared system temporary directory:
<tmp>/catalog-<base64 sha1 of the repo URL>
This path was fully determined by the repository URL and the location of the system temporary directory, so anyone else on the machine who knew which repository a victim would catalog could compute it in advance. The catalog service passed this path into its clone preparation step.
As a result, an attacker who placed a symlink at <tmp>/catalog-<hash> pointing at a directory of their choosing caused both the removal and the re-clone to operate through that symlink. Both landed at <attacker-chosen-parent>/<repoName>, outside the intended temporary root.
Terragrunt v1.1.1 no longer derives a predictable clone path, so an attacker can no longer position a symlink at a location known in advance.
Credit
We would like to thank (@br0x2) for discovering and responsibly disclosing this vulnerability.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/gruntwork-io/terragrunt"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.1.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-64672"
],
"database_specific": {
"cwe_ids": [
"CWE-377",
"CWE-59"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-15T18:21:35Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nTerragrunt\u0027s `terragrunt catalog` command clones each repository referenced in your catalog configuration into a temporary working directory. In affected versions, the clone path it derived was deterministic and sat under the shared system temporary directory, in the form `\u003ctmp\u003e/catalog-\u003cbase64 sha1 of the repo URL\u003e`. Because that path was predictable and Terragrunt followed a symlink already present there instead of rejecting it, a local attacker could plant a symlink at that path and cause Terragrunt to delete a directory and re-clone into it outside the intended temporary root.\n\n### Impact\n\nThis affected users who ran `terragrunt catalog` on a host they shared with other local users or processes they did not fully trust, such as a multi-user server or a shared CI runner. The attack required a local attacker: a separate local user or process able to write to the shared system temporary directory. It was not remotely exploitable, and the victim had to run `terragrunt catalog` while the attacker\u0027s symlink was already in place.\n\nBecause the predictable path depended only on the repository URL being cataloged and the location of the system temporary directory, the attacker could compute it in advance and plant a symlink there before the victim ran the command. When the victim ran `terragrunt catalog`, Terragrunt followed the symlink out of the intended temporary root, deleted an existing `\u003crepoName\u003e` directory under the attacker-chosen parent, and repopulated that path with the cloned repository contents. All of this happened in the security context of the user running Terragrunt.\n\nThe attacker controlled the parent directory the symlink pointed to, but not the leaf name: the leaf was fixed to `\u003crepoName\u003e`, derived from the repository URL the victim cataloged. The primitive was deletion of an existing `\u003crepoName\u003e` directory outside the temporary root, followed by a re-clone into that same path. On a single-user machine with no hostile local processes, exposure was minimal.\n\n### Affected Versions\n\n- Terragrunt `\u003c v1.1.1`\n\n### Patches\n\nThis vulnerability has been resolved in Terragrunt version `v1.1.1`.\n\nAll users are strongly advised to upgrade.\n\n### Workarounds\n\nIf you cannot upgrade immediately, ensure that you do not allow untrusted parties to control the values of `TMPDIR`, `TMP`, and `TEMP` in environments where you run `terragrunt catalog`.\n\n### Technical Details\n\nWhen you run `terragrunt catalog`, the catalog service iterates over the repositories in your configuration and prepares a local clone of each one. In affected versions, for a given repository URL it built a clone path by hashing the URL and joining the result under the shared system temporary directory:\n\n```\n\u003ctmp\u003e/catalog-\u003cbase64 sha1 of the repo URL\u003e\n```\n\nThis path was fully determined by the repository URL and the location of the system temporary directory, so anyone else on the machine who knew which repository a victim would catalog could compute it in advance. The catalog service passed this path into its clone preparation step.\n\nAs a result, an attacker who placed a symlink at `\u003ctmp\u003e/catalog-\u003chash\u003e` pointing at a directory of their choosing caused both the removal and the re-clone to operate through that symlink. Both landed at `\u003cattacker-chosen-parent\u003e/\u003crepoName\u003e`, outside the intended temporary root.\n\nTerragrunt `v1.1.1` no longer derives a predictable clone path, so an attacker can no longer position a symlink at a location known in advance.\n\n## Credit\n\nWe would like to thank ([@br0x2](https://github.com/br0x2)) for discovering and responsibly disclosing this vulnerability.",
"id": "GHSA-wv6g-x823-wx9m",
"modified": "2026-10-15T18:21:35Z",
"published": "2026-10-15T18:21:35Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gruntwork-io/terragrunt/security/advisories/GHSA-wv6g-x823-wx9m"
},
{
"type": "WEB",
"url": "https://github.com/gruntwork-io/terragrunt/pull/6438"
},
{
"type": "WEB",
"url": "https://github.com/gruntwork-io/terragrunt/commit/668891c5a2ad2996f134bb8b00098754674ea94a"
},
{
"type": "PACKAGE",
"url": "https://github.com/gruntwork-io/terragrunt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Terragrunt catalog predictable temp symlink clobber"
}
GHSA-WVHF-6GM4-V6JF
Vulnerability from github – Published: 2026-08-20 18:30 – Updated: 2026-08-20 18:30Kenwood DNR1007XR Firmware Update Link Following Code Execution Vulnerability. This vulnerability allows physically present attackers to execute arbitrary code on affected installations of Kenwood DNR1007XR devices. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the firmware update process. By creating a symbolic link, an attacker can abuse the service to move a file to an arbitrary location. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-28751.
{
"affected": [],
"aliases": [
"CVE-2026-18267"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-20T17:17:23Z",
"severity": "MODERATE"
},
"details": "Kenwood DNR1007XR Firmware Update Link Following Code Execution Vulnerability. This vulnerability allows physically present attackers to execute arbitrary code on affected installations of Kenwood DNR1007XR devices. Authentication is not required to exploit this vulnerability.\n\nThe specific flaw exists within the firmware update process. By creating a symbolic link, an attacker can abuse the service to move a file to an arbitrary location. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-28751.",
"id": "GHSA-wvhf-6gm4-v6jf",
"modified": "2026-08-20T18:30:54Z",
"published": "2026-08-20T18:30:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18267"
},
{
"type": "WEB",
"url": "https://www.kenwood.com/cs/ce/mm/firmware/2020/2020f/eng.html"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-26-484"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WVP4-7F3W-G9QJ
Vulnerability from github – Published: 2022-05-17 01:27 – Updated: 2022-05-17 01:27syncevo/installcheck-local.sh in syncevolution before 1.3.99.7 uses mktemp to create a safe temporary file but appends a suffix to the original filename and writes to this new filename, which allows local users to overwrite arbitrary files via a symlink attack on the new filename.
{
"affected": [],
"aliases": [
"CVE-2014-1639"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2014-01-28T00:55:00Z",
"severity": "LOW"
},
"details": "syncevo/installcheck-local.sh in syncevolution before 1.3.99.7 uses mktemp to create a safe temporary file but appends a suffix to the original filename and writes to this new filename, which allows local users to overwrite arbitrary files via a symlink attack on the new filename.",
"id": "GHSA-wvp4-7f3w-g9qj",
"modified": "2022-05-17T01:27:07Z",
"published": "2022-05-17T01:27:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2014-1639"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/90662"
},
{
"type": "WEB",
"url": "http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=736357"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2014/01/22/3"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2014/01/22/4"
},
{
"type": "WEB",
"url": "http://www.osvdb.org/102380"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/65098"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WW43-23JX-QCPC
Vulnerability from github – Published: 2022-12-22 21:30 – Updated: 2025-04-15 15:30When resolving a symlink such as file:///proc/self/fd/1, an error message may be produced where the symlink was resolved to a string containing unitialized memory in the buffer.
This bug only affects Thunderbird on Unix-based operated systems (Android, Linux, MacOS). Windows is unaffected.. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.
{
"affected": [],
"aliases": [
"CVE-2022-45412"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-12-22T20:15:00Z",
"severity": "HIGH"
},
"details": "When resolving a symlink such as \u003ccode\u003efile:///proc/self/fd/1\u003c/code\u003e, an error message may be produced where the symlink was resolved to a string containing unitialized memory in the buffer. \u003cbr\u003e*This bug only affects Thunderbird on Unix-based operated systems (Android, Linux, MacOS). Windows is unaffected.*. This vulnerability affects Firefox ESR \u003c 102.5, Thunderbird \u003c 102.5, and Firefox \u003c 107.",
"id": "GHSA-ww43-23jx-qcpc",
"modified": "2025-04-15T15:30:36Z",
"published": "2022-12-22T21:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-45412"
},
{
"type": "WEB",
"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1791029"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-47"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-48"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2022-49"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WW6F-FX4X-QW8G
Vulnerability from github – Published: 2022-05-24 17:32 – Updated: 2022-05-24 17:32checkpath in OpenRC through 0.42.1 might allow local users to take ownership of arbitrary files because a non-terminal path component can be a symlink.
{
"affected": [],
"aliases": [
"CVE-2018-21269"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2020-10-27T04:15:00Z",
"severity": "MODERATE"
},
"details": "checkpath in OpenRC through 0.42.1 might allow local users to take ownership of arbitrary files because a non-terminal path component can be a symlink.",
"id": "GHSA-ww6f-fx4x-qw8g",
"modified": "2022-05-24T17:32:13Z",
"published": "2022-05-24T17:32:13Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-21269"
},
{
"type": "WEB",
"url": "https://github.com/OpenRC/openrc/issues/201"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WW8G-33X9-V3QW
Vulnerability from github – Published: 2022-05-24 16:54 – Updated: 2023-02-24 00:30IBM Informix Dynamic Server Enterprise Edition 12.1 could allow a local user logged in with database administrator user to gain root privileges through a symbolic link vulnerability in onmode. IBM X-Force ID: 144430.
{
"affected": [],
"aliases": [
"CVE-2018-1630"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-08-20T19:15:00Z",
"severity": "HIGH"
},
"details": "IBM Informix Dynamic Server Enterprise Edition 12.1 could allow a local user logged in with database administrator user to gain root privileges through a symbolic link vulnerability in onmode. IBM X-Force ID: 144430.",
"id": "GHSA-ww8g-33x9-v3qw",
"modified": "2023-02-24T00:30:16Z",
"published": "2022-05-24T16:54:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-1630"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/144430"
},
{
"type": "WEB",
"url": "https://security.netapp.com/advisory/ntap-20190903-0002"
},
{
"type": "WEB",
"url": "http://www.ibm.com/support/docview.wss?uid=ibm10964987"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WWCF-37PW-HPQR
Vulnerability from github – Published: 2026-09-08 18:33 – Updated: 2026-09-08 18:33Improper link resolution before file access ('link following') in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.
{
"affected": [],
"aliases": [
"CVE-2026-83999"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-08T18:21:10Z",
"severity": "HIGH"
},
"details": "Improper link resolution before file access (\u0027link following\u0027) in Windows Resilient File System (ReFS) Deduplication Service allows an authorized attacker to elevate privileges locally.",
"id": "GHSA-wwcf-37pw-hpqr",
"modified": "2026-09-08T18:33:39Z",
"published": "2026-09-08T18:33:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83999"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83999"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WWFQ-CQ3F-8QX7
Vulnerability from github – Published: 2025-02-05 00:31 – Updated: 2025-02-05 00:31Parallels Desktop Technical Data Reporter Link Following Local Privilege Escalation Vulnerability. This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Desktop. An attacker must first obtain the ability to execute low-privileged code on the target host system in order to exploit this vulnerability.
The specific flaw exists within the Technical Data Reporter component. By creating a symbolic link, an attacker can abuse the service to change the permissions of arbitrary files. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root. Was ZDI-CAN-25014.
{
"affected": [],
"aliases": [
"CVE-2025-0413"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-02-05T00:15:28Z",
"severity": "HIGH"
},
"details": "Parallels Desktop Technical Data Reporter Link Following Local Privilege Escalation Vulnerability. \nThis vulnerability allows local attackers to escalate privileges on affected installations of Parallels Desktop. An attacker must first obtain the ability to execute low-privileged code on the target host system in order to exploit this vulnerability.\n\nThe specific flaw exists within the Technical Data Reporter component. By creating a symbolic link, an attacker can abuse the service to change the permissions of arbitrary files. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root. Was ZDI-CAN-25014.",
"id": "GHSA-wwfq-cq3f-8qx7",
"modified": "2025-02-05T00:31:13Z",
"published": "2025-02-05T00:31:13Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-0413"
},
{
"type": "WEB",
"url": "https://kb.parallels.com/130212"
},
{
"type": "WEB",
"url": "https://www.zerodayinitiative.com/advisories/ZDI-25-082"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WWMX-3P39-RX9C
Vulnerability from github – Published: 2026-07-01 21:36 – Updated: 2026-07-06 21:30Dell Device Management Agent, versions prior to DDMA 26.05, contain an Improper Link Resolution Before File Access ('Link Following’) vulnerability. A low privileged attacker with local access could potentially exploit this vulnerability, leading to Elevation of Privileges.
{
"affected": [],
"aliases": [
"CVE-2026-41121"
],
"database_specific": {
"cwe_ids": [
"CWE-59"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-01T19:16:51Z",
"severity": "HIGH"
},
"details": "Dell Device Management Agent, versions prior to DDMA 26.05, contain an Improper Link Resolution Before File Access (\u0027Link Following\u2019) vulnerability. A low privileged attacker with local access could\u00a0potentially exploit this vulnerability, leading to Elevation of Privileges.",
"id": "GHSA-wwmx-3p39-rx9c",
"modified": "2026-07-06T21:30:28Z",
"published": "2026-07-01T21:36:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41121"
},
{
"type": "WEB",
"url": "https://www.dell.com/support/kbdoc/en-us/000473690/dsa-2026-258"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Mitigation MIT-48.1
Strategy: Separation of Privilege
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
CAPEC-132: Symlink Attack
An adversary positions a symbolic link in such a manner that the targeted user or application accesses the link's endpoint, assuming that it is accessing a file with the link's name.
CAPEC-17: Using Malicious Files
An attack of this type exploits a system's configuration that allows an adversary to either directly access an executable file, for example through shell access; or in a possible worst case allows an adversary to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
CAPEC-35: Leverage Executable Code in Non-Executable Files
An attack of this type exploits a system's trust in configuration and resource files. When the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high.
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.