CVE-2026-66294 (GCVE-0-2026-66294)
Vulnerability from cvelistv5 – Published: 2026-11-06 10:16 – Updated: 2026-11-06 10:16
VLAI
EPSS
VEX
Title
XML injection in Saxy via unescaped CDATA section terminator
Summary
XML injection in the Saxy XML encoder. Saxy.Encoder.cdata/1 serializes a {:cdata, characters} node by wrapping the supplied characters between <![CDATA[ and ]]> and passing the payload through byte for byte. The encoder's character-data and attribute-value paths escape the XML metacharacters <, >, &, ", and ', but the CDATA path applies no neutralization at all. XML provides no character escaping mechanism inside a CDATA section, so the only correct way to represent a ]]> substring is to split the section and rejoin it as ]]]]><![CDATA[>. Saxy neither performs that split nor rejects the substring.
An application that renders untrusted text as CDATA, by building the node with Saxy.XML.cdata/1 and serializing it with Saxy.encode!/2 or Saxy.encode_to_iodata!/2, therefore lets an attacker terminate the section at a position of their choosing. Everything supplied after the ]]> is emitted outside any CDATA context and is parsed as markup, so a single attacker-controlled text field becomes attacker-controlled document structure: arbitrary sibling elements and attributes that the application never built. Downstream consumers of the serialized document accept the injected markup as genuine. Services that generate SOAP envelopes, RSS or Atom feeds, sitemaps, SVG, or XML exports from user-supplied content can have trusted fields forged or overridden. Applications that never place untrusted text in a CDATA node are not affected.
This issue affects saxy: from 0.7.0 before 1.7.0.
Severity
CWE
- CWE-91 - XML Injection
Assigner
EEF
CNA
References
5 references
| URL | Tags |
|---|---|
| https://github.com/qcam/saxy/security/advisories/… | vendor-advisoryrelated |
| https://cna.erlef.org/cves/CVE-2026-66294.html | related |
| https://osv.dev/vulnerability/EEF-CVE-2026-66294 | related |
| https://github.com/qcam/saxy/commit/7266632e94078… | related |
| https://github.com/qcam/saxy/commit/71d99fae12f1d… | patch |
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"collectionURL": "https://repo.hex.pm",
"cpes": [
"cpe:2.3:a:qcam:saxy:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.Saxy\u0027",
"\u0027Elixir.Saxy.Encoder\u0027",
"\u0027Elixir.Saxy.XML\u0027"
],
"packageName": "saxy",
"packageURL": "pkg:hex/saxy",
"product": "saxy",
"programFiles": [
"lib/saxy.ex",
"lib/saxy/encoder.ex",
"lib/saxy/xml.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.Saxy\u0027:encode!/2"
},
{
"name": "\u0027Elixir.Saxy\u0027:encode_to_iodata!/2"
},
{
"name": "\u0027Elixir.Saxy.Encoder\u0027:encode_to_iodata/2"
},
{
"name": "\u0027Elixir.Saxy.Encoder\u0027:cdata/1"
},
{
"name": "\u0027Elixir.Saxy.XML\u0027:cdata/1"
}
],
"repo": "https://github.com/qcam/saxy",
"vendor": "qcam",
"versions": [
{
"lessThan": "1.7.0",
"status": "affected",
"version": "0.7.0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:qcam:saxy:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.Saxy\u0027",
"\u0027Elixir.Saxy.Encoder\u0027",
"\u0027Elixir.Saxy.XML\u0027"
],
"packageName": "qcam/saxy",
"packageURL": "pkg:github/qcam/saxy",
"product": "saxy",
"programFiles": [
"lib/saxy.ex",
"lib/saxy/encoder.ex",
"lib/saxy/xml.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.Saxy\u0027:encode!/2"
},
{
"name": "\u0027Elixir.Saxy\u0027:encode_to_iodata!/2"
},
{
"name": "\u0027Elixir.Saxy.Encoder\u0027:encode_to_iodata/2"
},
{
"name": "\u0027Elixir.Saxy.Encoder\u0027:cdata/1"
},
{
"name": "\u0027Elixir.Saxy.XML\u0027:cdata/1"
}
],
"repo": "https://github.com/qcam/saxy",
"vendor": "qcam",
"versions": [
{
"lessThan": "71d99fae12f1d6596f5edb57b71f26ba854f4d33",
"status": "affected",
"version": "7266632e9407842f28ffac254c56dc41210a5690",
"versionType": "git"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:qcam:saxy:*:*:*:*:*:*:*:*",
"versionEndExcluding": "1.7.0",
"versionStartIncluding": "0.7.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Peter Ullrich"
},
{
"lang": "en",
"type": "reporter",
"value": "Peter Ullrich"
},
{
"lang": "en",
"type": "remediation developer",
"value": "Peter Ullrich"
},
{
"lang": "en",
"type": "remediation reviewer",
"value": "C\u1ea9m Hu\u1ef3nh"
},
{
"lang": "en",
"type": "analyst",
"value": "Jonatan M\u00e4nnchen / EEF"
},
{
"lang": "en",
"type": "coordinator",
"value": "Peter Ullrich"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eXML injection in the Saxy XML encoder. \u003ccode\u003eSaxy.Encoder.cdata/1\u003c/code\u003e serializes a \u003ccode\u003e{:cdata, characters}\u003c/code\u003e node by wrapping the supplied characters between \u003ccode\u003e\u0026lt;![CDATA[\u003c/code\u003e and \u003ccode\u003e]]\u0026gt;\u003c/code\u003e and passing the payload through byte for byte. The encoder\u0027s character-data and attribute-value paths escape the XML metacharacters \u003ccode\u003e\u0026lt;\u003c/code\u003e, \u003ccode\u003e\u0026gt;\u003c/code\u003e, \u003ccode\u003e\u0026amp;\u003c/code\u003e, \u003ccode\u003e\"\u003c/code\u003e, and \u003ccode\u003e\u0027\u003c/code\u003e, but the CDATA path applies no neutralization at all. XML provides no character escaping mechanism inside a CDATA section, so the only correct way to represent a \u003ccode\u003e]]\u0026gt;\u003c/code\u003e substring is to split the section and rejoin it as \u003ccode\u003e]]]]\u0026gt;\u0026lt;![CDATA[\u0026gt;\u003c/code\u003e. Saxy neither performs that split nor rejects the substring.\u003c/p\u003e\n\u003cp\u003eAn application that renders untrusted text as CDATA, by building the node with \u003ccode\u003eSaxy.XML.cdata/1\u003c/code\u003e and serializing it with \u003ccode\u003eSaxy.encode!/2\u003c/code\u003e or \u003ccode\u003eSaxy.encode_to_iodata!/2\u003c/code\u003e, therefore lets an attacker terminate the section at a position of their choosing. Everything supplied after the \u003ccode\u003e]]\u0026gt;\u003c/code\u003e is emitted outside any CDATA context and is parsed as markup, so a single attacker-controlled text field becomes attacker-controlled document structure: arbitrary sibling elements and attributes that the application never built. Downstream consumers of the serialized document accept the injected markup as genuine. Services that generate SOAP envelopes, RSS or Atom feeds, sitemaps, SVG, or XML exports from user-supplied content can have trusted fields forged or overridden. Applications that never place untrusted text in a CDATA node are not affected.\u003c/p\u003e\n\u003cp\u003eThis issue affects saxy: from 0.7.0 before 1.7.0.\u003c/p\u003e"
},
{
"base64": false,
"type": "text/markdown",
"value": "XML injection in the Saxy XML encoder. `Saxy.Encoder.cdata/1` serializes a `{:cdata, characters}` node by wrapping the supplied characters between `\u003c![CDATA[` and `]]\u003e` and passing the payload through byte for byte. The encoder\u0027s character-data and attribute-value paths escape the XML metacharacters `\u003c`, `\u003e`, `\u0026`, `\"`, and `\u0027`, but the CDATA path applies no neutralization at all. XML provides no character escaping mechanism inside a CDATA section, so the only correct way to represent a `]]\u003e` substring is to split the section and rejoin it as `]]]]\u003e\u003c![CDATA[\u003e`. Saxy neither performs that split nor rejects the substring.\n\nAn application that renders untrusted text as CDATA, by building the node with `Saxy.XML.cdata/1` and serializing it with `Saxy.encode!/2` or `Saxy.encode_to_iodata!/2`, therefore lets an attacker terminate the section at a position of their choosing. Everything supplied after the `]]\u003e` is emitted outside any CDATA context and is parsed as markup, so a single attacker-controlled text field becomes attacker-controlled document structure: arbitrary sibling elements and attributes that the application never built. Downstream consumers of the serialized document accept the injected markup as genuine. Services that generate SOAP envelopes, RSS or Atom feeds, sitemaps, SVG, or XML exports from user-supplied content can have trusted fields forged or overridden. Applications that never place untrusted text in a CDATA node are not affected.\n\nThis issue affects saxy: from 0.7.0 before 1.7.0."
}
],
"value": "XML injection in the Saxy XML encoder. Saxy.Encoder.cdata/1 serializes a {:cdata, characters} node by wrapping the supplied characters between \u003c![CDATA[ and ]]\u003e and passing the payload through byte for byte. The encoder\u0027s character-data and attribute-value paths escape the XML metacharacters \u003c, \u003e, \u0026, \", and \u0027, but the CDATA path applies no neutralization at all. XML provides no character escaping mechanism inside a CDATA section, so the only correct way to represent a ]]\u003e substring is to split the section and rejoin it as ]]]]\u003e\u003c![CDATA[\u003e. Saxy neither performs that split nor rejects the substring.\n\nAn application that renders untrusted text as CDATA, by building the node with Saxy.XML.cdata/1 and serializing it with Saxy.encode!/2 or Saxy.encode_to_iodata!/2, therefore lets an attacker terminate the section at a position of their choosing. Everything supplied after the ]]\u003e is emitted outside any CDATA context and is parsed as markup, so a single attacker-controlled text field becomes attacker-controlled document structure: arbitrary sibling elements and attributes that the application never built. Downstream consumers of the serialized document accept the injected markup as genuine. Services that generate SOAP envelopes, RSS or Atom feeds, sitemaps, SVG, or XML exports from user-supplied content can have trusted fields forged or overridden. Applications that never place untrusted text in a CDATA node are not affected.\n\nThis issue affects saxy: from 0.7.0 before 1.7.0."
}
],
"impacts": [
{
"capecId": "CAPEC-250",
"descriptions": [
{
"lang": "en",
"value": "CAPEC-250 XML Injection"
}
]
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "LOCAL",
"baseScore": 2.1,
"baseSeverity": "LOW",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "LOW",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "LOW",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-91",
"description": "CWE-91 XML Injection",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-11-06T10:16:49.656Z",
"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"shortName": "EEF"
},
"references": [
{
"tags": [
"vendor-advisory",
"related"
],
"url": "https://github.com/qcam/saxy/security/advisories/GHSA-hq6g-j46w-wx72"
},
{
"name": "EEF CNA record for CVE-2026-66294",
"tags": [
"related"
],
"url": "https://cna.erlef.org/cves/CVE-2026-66294.html"
},
{
"name": "OSV record EEF-CVE-2026-66294",
"tags": [
"related"
],
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-66294"
},
{
"name": "Introducing commit 7266632 in qcam/saxy",
"tags": [
"related"
],
"url": "https://github.com/qcam/saxy/commit/7266632e9407842f28ffac254c56dc41210a5690"
},
{
"name": "Fix commit 71d99fa in qcam/saxy",
"tags": [
"patch"
],
"url": "https://github.com/qcam/saxy/commit/71d99fae12f1d6596f5edb57b71f26ba854f4d33"
}
],
"source": {
"discovery": "EXTERNAL"
},
"title": "XML injection in Saxy via unescaped CDATA section terminator",
"workarounds": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "\u003cp\u003eRender untrusted text as ordinary character data instead of CDATA, by passing a plain string or \u003ccode\u003eSaxy.XML.characters/1\u003c/code\u003e to the element builder. That encoder path escapes the XML metacharacters and preserves the same text content.\u003c/p\u003e\n\u003cp\u003eIf a CDATA section is required, split the terminator in application code before building the node: replace every occurrence of \u003ccode\u003e]]\u0026gt;\u003c/code\u003e in the untrusted text with \u003ccode\u003e]]]]\u0026gt;\u0026lt;![CDATA[\u0026gt;\u003c/code\u003e and pass the result to \u003ccode\u003eSaxy.XML.cdata/1\u003c/code\u003e. Once the encoder wraps that payload, the output is the standard split encoding.\u003c/p\u003e"
},
{
"base64": false,
"type": "text/markdown",
"value": "Render untrusted text as ordinary character data instead of CDATA, by passing a plain string or `Saxy.XML.characters/1` to the element builder. That encoder path escapes the XML metacharacters and preserves the same text content.\n\nIf a CDATA section is required, split the terminator in application code before building the node: replace every occurrence of `]]\u003e` in the untrusted text with `]]]]\u003e\u003c![CDATA[\u003e` and pass the result to `Saxy.XML.cdata/1`. Once the encoder wraps that payload, the output is the standard split encoding."
}
],
"value": "Render untrusted text as ordinary character data instead of CDATA, by passing a plain string or Saxy.XML.characters/1 to the element builder. That encoder path escapes the XML metacharacters and preserves the same text content.\n\nIf a CDATA section is required, split the terminator in application code before building the node: replace every occurrence of ]]\u003e in the untrusted text with ]]]]\u003e\u003c![CDATA[\u003e and pass the result to Saxy.XML.cdata/1. Once the encoder wraps that payload, the output is the standard split encoding."
}
]
}
},
"cveMetadata": {
"assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"assignerShortName": "EEF",
"cveId": "CVE-2026-66294",
"datePublished": "2026-11-06T10:16:49.656Z",
"dateReserved": "2026-07-24T14:10:01.114Z",
"dateUpdated": "2026-11-06T10:16:49.656Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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