CWE-611
AllowedImproper Restriction of XML External Entity Reference
Abstraction: Base · Status: Draft
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
1825 vulnerabilities reference this CWE, most recent first.
GHSA-H67G-969J-MGR3
Vulnerability from github – Published: 2022-05-24 16:48 – Updated: 2024-04-04 01:02BlogEngine.NET 3.3.7 and earlier allows XXE via an apml file to syndication.axd.
{
"affected": [],
"aliases": [
"CVE-2019-11392"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-06-21T19:15:00Z",
"severity": "HIGH"
},
"details": "BlogEngine.NET 3.3.7 and earlier allows XXE via an apml file to syndication.axd.",
"id": "GHSA-h67g-969j-mgr3",
"modified": "2024-04-04T01:02:36Z",
"published": "2022-05-24T16:48:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-11392"
},
{
"type": "WEB",
"url": "https://www.securitymetrics.com/blog/blogenginenet-xml-external-entity-attacks"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H755-H99P-9FFV
Vulnerability from github – Published: 2022-05-14 01:40 – Updated: 2024-01-08 20:11An issue was discovered in weixin-java-tools. There is an XXE vulnerability in the getXmlDoc method of the BaseWxPayResult.java file. NOTE: this issue exists because of an incomplete fix for CVE-2018-20318.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "com.github.binarywang:weixin-java-common"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.3.2.B"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2019-5312"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": true,
"github_reviewed_at": "2024-01-08T20:11:00Z",
"nvd_published_at": "2019-01-04T16:29:00Z",
"severity": "CRITICAL"
},
"details": "An issue was discovered in weixin-java-tools. There is an XXE vulnerability in the getXmlDoc method of the BaseWxPayResult.java file. NOTE: this issue exists because of an incomplete fix for CVE-2018-20318.",
"id": "GHSA-h755-h99p-9ffv",
"modified": "2024-01-08T20:11:00Z",
"published": "2022-05-14T01:40:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-5312"
},
{
"type": "WEB",
"url": "https://github.com/Wechat-Group/WxJava/issues/903"
},
{
"type": "WEB",
"url": "https://github.com/Wechat-Group/WxJava/issues/903#issuecomment-453747039"
},
{
"type": "WEB",
"url": "https://github.com/Wechat-Group/WxJava/commit/8ec61d1328f50e23cd14285a950ca57a088b32b2"
}
],
"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"
}
],
"summary": "XML External Entity Reference in weixin-java-tools"
}
GHSA-H7PC-9M8F-584G
Vulnerability from github – Published: 2021-12-09 00:01 – Updated: 2021-12-14 00:01National Library of the Netherlands multiNER <= c0440948057afc6e3d6b4903a7c05e666b94a3bc is affected by an XML External Entity (XXE) vulnerability in multiNER/ner.py. Since XML parsing resolves external entities, a malicious XML stream could leak internal files and/or cause a DoS.
{
"affected": [],
"aliases": [
"CVE-2021-44557"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-12-08T12:15:00Z",
"severity": "CRITICAL"
},
"details": "National Library of the Netherlands multiNER \u003c= c0440948057afc6e3d6b4903a7c05e666b94a3bc is affected by an XML External Entity (XXE) vulnerability in multiNER/ner.py. Since XML parsing resolves external entities, a malicious XML stream could leak internal files and/or cause a DoS.",
"id": "GHSA-h7pc-9m8f-584g",
"modified": "2021-12-14T00:01:39Z",
"published": "2021-12-09T00:01:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-44557"
},
{
"type": "WEB",
"url": "https://github.com/KBNLresearch/multiNER/pull/3"
},
{
"type": "WEB",
"url": "https://github.com/KBNLresearch/multiNER"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-H7QF-QMF3-85QG
Vulnerability from github – Published: 2025-06-25 14:14 – Updated: 2025-06-25 14:14Summary
A critical XML External Entity (XXE) vulnerability exists in the xunit-xml-plugin used by Allure 2. The plugin fails to securely configure the XML parser (DocumentBuilderFactory) and allows external entity expansion when processing test result .xml files. This allows attackers to read arbitrary files from the file system and potentially trigger server-side request forgery (SSRF).
Details
In \allure2-main\plugins\xunit-xml-plugin\src\main\java\io\qameta\allure\xunitxml\XunitXmlPlugin.java the application uses DocumentBuilderFactory without disabling DTDs or external entities. By generating a report with a malicious xml file within it, an attacker can perform XXE to leverage SSRF, or to read system files.
PoC
To recreate this vulnerability, you need to install allure for command-line (In my POC I used a Windows 11 Machine).
- Create a folder called
allure, and within it, create a malicious XML file. I will attach my SSRF and file reading payloads, however, for the rest of the POC, I will focus on reading system files for better screenshots.
SSRF (replace webhook link with your own)
Reading System Files
- Put the malicious .xml file into the
alluredirectory created previously - Run the following command to run the report
allure generate C:\path\to\directory\allure -o report --clean - To view and confirm the executed payload, run
allure open report - When the report opens, confirm the payload executedby going to
Categories > Product defects > <payload response>
Impact
The explained XXE vulnerability can lead to Arbitrary File Disclosure and Server-Side Request Forgery. This exploitation can also be carried out silently, meaning it can be carried out without user interaction if the tool is automated within an application, and can go undetected with a carefully crafted payload. This could allow a malicious actor to view other source codes which may contain API or product keys, internal application URLs, or other secret items. This makes it an especially high risk when ran within a CI/CD platform.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.34.0"
},
"package": {
"ecosystem": "Maven",
"name": "io.qameta.allure.plugins:xunit-xml-plugin"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.34.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.34.0"
},
"package": {
"ecosystem": "Maven",
"name": "io.qameta.allure.plugins:junit-xml-plugin"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.34.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.34.0"
},
"package": {
"ecosystem": "Maven",
"name": "io.qameta.allure.plugins:trx-plugin"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.34.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-52888"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": true,
"github_reviewed_at": "2025-06-25T14:14:09Z",
"nvd_published_at": "2025-06-24T20:15:26Z",
"severity": "HIGH"
},
"details": "### Summary\nA critical XML External Entity (XXE) vulnerability exists in the xunit-xml-plugin used by Allure 2. The plugin fails to securely configure the XML parser (`DocumentBuilderFactory`) and allows external entity expansion when processing test result .xml files. This allows attackers to read arbitrary files from the file system and potentially trigger server-side request forgery (SSRF).\n\n### Details\nIn `\\allure2-main\\plugins\\xunit-xml-plugin\\src\\main\\java\\io\\qameta\\allure\\xunitxml\\XunitXmlPlugin.java` the application uses `DocumentBuilderFactory` without disabling DTDs or external entities. By generating a report with a malicious xml file within it, an attacker can perform XXE to leverage SSRF, or to read system files.\n\n### PoC\nTo recreate this vulnerability, you need to install allure for command-line (In my POC I used a Windows 11 Machine). \n\n1. Create a folder called `allure`, and within it, create a malicious XML file. I will attach my SSRF and file reading payloads, however, for the rest of the POC, I will focus on reading system files for better screenshots.\n##SSRF (replace webhook link with your own)\n\n\n##Reading System Files\n\n\n2. Put the malicious .xml file into the `allure` directory created previously\n3. Run the following command to run the report `allure generate C:\\path\\to\\directory\\allure -o report --clean`\n4. To view and confirm the executed payload, run `allure open report`\n5. When the report opens, confirm the payload executedby going to `Categories \u003e Product defects \u003e \u003cpayload response\u003e`\n\n\n\n\n### Impact\nThe explained XXE vulnerability can lead to Arbitrary File Disclosure and Server-Side Request Forgery. This exploitation can also be carried out silently, meaning it can be carried out without user interaction if the tool is automated within an application, and can go undetected with a carefully crafted payload. This could allow a malicious actor to view other source codes which may contain API or product keys, internal application URLs, or other secret items. This makes it an especially high risk when ran within a CI/CD platform.",
"id": "GHSA-h7qf-qmf3-85qg",
"modified": "2025-06-25T14:14:09Z",
"published": "2025-06-25T14:14:09Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/allure-framework/allure2/security/advisories/GHSA-h7qf-qmf3-85qg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-52888"
},
{
"type": "WEB",
"url": "https://github.com/allure-framework/allure2/commit/cbcb33719851ff70adce85d38e15d20fc58d4eb7"
},
{
"type": "PACKAGE",
"url": "https://github.com/allure-framework/allure2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Allure Report allows Improper XXE Restriction via DocumentBuilderFactory"
}
GHSA-H7WH-8CWV-QQM6
Vulnerability from github – Published: 2023-04-26 21:30 – Updated: 2024-04-04 03:42Zoho ManageEngine ServiceDesk Plus through 14104 allows admin users to conduct an XXE attack.
{
"affected": [],
"aliases": [
"CVE-2023-29443"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-04-26T21:15:08Z",
"severity": "MODERATE"
},
"details": "Zoho ManageEngine ServiceDesk Plus through 14104 allows admin users to conduct an XXE attack.",
"id": "GHSA-h7wh-8cwv-qqm6",
"modified": "2024-04-04T03:42:09Z",
"published": "2023-04-26T21:30:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-29443"
},
{
"type": "WEB",
"url": "https://www.manageengine.com/products/service-desk/CVE-2023-29443.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H827-X5F6-X45J
Vulnerability from github – Published: 2022-05-24 19:01 – Updated: 2022-05-24 19:01IBM QRadar SIEM 7.3 and 7.4 may vulnerable to a XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this vulnerability to expose sensitive information or consume memory resources. IBM X-Force ID: 193245.
{
"affected": [],
"aliases": [
"CVE-2020-5013"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-05-05T16:15:00Z",
"severity": "HIGH"
},
"details": "IBM QRadar SIEM 7.3 and 7.4 may vulnerable to a XML External Entity Injection (XXE) attack when processing XML data. A remote attacker could exploit this vulnerability to expose sensitive information or consume memory resources. IBM X-Force ID: 193245.",
"id": "GHSA-h827-x5f6-x45j",
"modified": "2022-05-24T19:01:24Z",
"published": "2022-05-24T19:01:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-5013"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/193245"
},
{
"type": "WEB",
"url": "https://www.ibm.com/support/pages/node/6449690"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-H82J-45QH-F65R
Vulnerability from github – Published: 2026-08-31 18:31 – Updated: 2026-09-28 18:31A flaw was found in RESTEasy's SourceProvider. This vulnerability allows an unauthenticated attacker to perform an unauthenticated remote file read. By sending a specially crafted XML body with a DOCTYPE declaration referencing external entities to an endpoint that accepts application/xml and returns Source or StreamSource, the server can be tricked into resolving the entity and including sensitive file contents in the HTTP response. This is due to the SourceProvider.writeTo() method creating a SAXParser without disabling external entity resolution, leading to an XML External Entity (XXE) vulnerability.
{
"affected": [],
"aliases": [
"CVE-2026-17615"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-31T17:17:37Z",
"severity": "HIGH"
},
"details": "A flaw was found in RESTEasy\u0027s SourceProvider. This vulnerability allows an unauthenticated attacker to perform an unauthenticated remote file read. By sending a specially crafted XML body with a DOCTYPE declaration referencing external entities to an endpoint that accepts application/xml and returns Source or StreamSource, the server can be tricked into resolving the entity and including sensitive file contents in the HTTP response. This is due to the SourceProvider.writeTo() method creating a SAXParser without disabling external entity resolution, leading to an XML External Entity (XXE) vulnerability.",
"id": "GHSA-h82j-45qh-f65r",
"modified": "2026-09-28T18:31:06Z",
"published": "2026-08-31T18:31:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-17615"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:62515"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:62555"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:63302"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:68277"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:68278"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:72424"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2026-17615"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2507635"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H87W-WJ3V-299R
Vulnerability from github – Published: 2023-07-19 06:31 – Updated: 2024-04-04 06:16XBRL data create application version 7.0 and earlier improperly restricts XML external entity references (XXE). By processing a specially crafted XBRL file, arbitrary files on the system may be read by an attacker.
{
"affected": [],
"aliases": [
"CVE-2023-32635"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-07-19T06:15:12Z",
"severity": "MODERATE"
},
"details": "XBRL data create application version 7.0 and earlier improperly restricts XML external entity references (XXE). By processing a specially crafted XBRL file, arbitrary files on the system may be read by an attacker.",
"id": "GHSA-h87w-wj3v-299r",
"modified": "2024-04-04T06:16:55Z",
"published": "2023-07-19T06:31:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-32635"
},
{
"type": "WEB",
"url": "https://jvn.jp/en/jp/JVN44726469"
},
{
"type": "WEB",
"url": "https://submit2.edinet-fsa.go.jp"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H896-MX9X-G32G
Vulnerability from github – Published: 2019-05-29 18:15 – Updated: 2022-11-17 17:55Apache Camel prior to 2.24.0 contains an XML external entity injection (XXE) vulnerability (CWE-611) due to using an outdated vulnerable JSON-lib library. This affects only the camel-xmljson component, which was removed.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "org.apache.camel:camel-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.24.0"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Maven",
"name": "org.apache.camel:camel-xmljson"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "2.23.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2019-0188"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": true,
"github_reviewed_at": "2019-05-29T18:15:06Z",
"nvd_published_at": "2019-05-28T19:29:00Z",
"severity": "HIGH"
},
"details": "Apache Camel prior to 2.24.0 contains an XML external entity injection (XXE) vulnerability (CWE-611) due to using an outdated vulnerable JSON-lib library. This affects only the camel-xmljson component, which was removed.",
"id": "GHSA-h896-mx9x-g32g",
"modified": "2022-11-17T17:55:41Z",
"published": "2019-05-29T18:15:50Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-0188"
},
{
"type": "WEB",
"url": "https://github.com/apache/camel/blob/master/docs/user-manual/en/security-advisories/CVE-2019-0188.txt.asc"
},
{
"type": "WEB",
"url": "https://issues.apache.org/jira/browse/TAMAYA-410"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/00118387610522b107cbdcec5369ddd512b576ff0236a02bfca12f44@%3Cusers.camel.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/45349f8bd98c1c13a84beddede18fe79b8619ebab99d90f1fb43d7ab@%3Cdev.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/61601cda2c5f9832184ea14647b0c0589c94126a460c8eb196be1313@%3Ccommits.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/63d1cec8541befeb59dbed23a6b227bdcca7674aa234fb43354dac82@%3Ccommits.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/6fefbd90f7fb4c8412d85ea3e9e97a4b76b47e206f502c73c29dc0b7@%3Ccommits.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/84ba9b79e801a4148dde73d1969cdae0247d11ff63de7ce11b394dc5@%3Ccommits.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/ac51944aef91dd5006b8510b0bef337adaccfe962fb90e7af9c22db4@%3Cissues.activemq.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/eed73fc18d4fa3e2341cd0ab101b47f06b16c7efc1cb73791c524c9d@%3Cdev.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread.html/fe74d173689600d9a395d026f0bf5d154c0bf7bd195ecfbc2c987036@%3Cdev.tamaya.apache.org%3E"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpujan2021.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpujul2020.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html"
},
{
"type": "WEB",
"url": "http://jvn.jp/en/jp/JVN71498764/index.html"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2019/05/24/2"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/108422"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "XML External Entity injection in Apache Camel"
}
GHSA-H8F7-2HGQ-GR97
Vulnerability from github – Published: 2023-08-10 21:30 – Updated: 2023-11-03 21:30Ivanti Avalanche decodeToMap XML External Entity Processing. Fixed in version 6.4.1.
{
"affected": [],
"aliases": [
"CVE-2023-32567"
],
"database_specific": {
"cwe_ids": [
"CWE-611"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-08-10T19:15:09Z",
"severity": "CRITICAL"
},
"details": "Ivanti Avalanche decodeToMap XML External Entity Processing. Fixed in version 6.4.1.",
"id": "GHSA-h8f7-2hgq-gr97",
"modified": "2023-11-03T21:30:19Z",
"published": "2023-08-10T21:30:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-32567"
},
{
"type": "WEB",
"url": "https://download.wavelink.com/Files/avalanche_v6.4.1.236_release_notes.txt"
},
{
"type": "WEB",
"url": "https://forums.ivanti.com/s/article/Avalanche-Vulnerabilities-Addressed-in-6-4-1?language=en_US"
}
],
"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
Many XML parsers and validators can be configured to disable external entity expansion.
CAPEC-221: Data Serialization External Entities Blowup
This attack takes advantage of the entity replacement property of certain data serialization languages (e.g., XML, YAML, etc.) where the value of the replacement is a URI. A well-crafted file could have the entity refer to a URI that consumes a large amount of resources to create a denial of service condition. This can cause the system to either freeze, crash, or execute arbitrary code depending on the URI.