{"id":"CVE-2026-47079","state":"PUBLISHED","title":"Round-trip Corruption via Improper Entity Escaping in xml_builder","description":"Inappropriate Encoding for Output Context vulnerability in joshnuss xml_builder (XmlBuilder module) allows Content Spoofing, Cross-site Scripting.\n\nThis vulnerability is associated with program files lib/xml_builder.ex and program routines XmlBuilder.generate/1, XmlBuilder.generate/2, XmlBuilder.escape_string/1, XmlBuilder.escape_entity/1.\n\nXmlBuilder.generate/1 does not escape literal & characters in text or attribute values when they are followed by an entity-like token (lt;, gt;, amp;, quot;, apos;). As a result, attacker-supplied input such as &lt;script&gt; is emitted verbatim into the serialized XML rather than being escaped to &amp;lt;script&amp;gt;. When a downstream XML parser later reads the document, it decodes the entity sequences into the literal characters <script>, promoting inert-looking text into real markup. This allows an attacker to bypass upstream filters that block raw < and > characters, injecting markup into any downstream consumer that parses the produced XML and renders the text content in a markup-sensitive context (HTML, SVG, RSS/Atom feeds). Both element text and attribute values are affected.\n\nThis issue affects xml_builder: from 0.0.6 before 2.4.1.","publishedAt":"2026-08-21T09:52:44.178Z","updatedAt":"2026-08-21T12:19:47.179Z","severity":{"score":2.1,"label":"Low","version":"4.0","vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N","source":"EEF"},"assigner":"EEF","products":["joshnuss xml_builder"],"affected":[{"vendor":"joshnuss","product":"xml_builder","packageName":"xml_builder","packageURL":"pkg:hex/xml_builder","defaultStatus":"unaffected","versions":[{"version":"0.0.6","status":"affected","lessThan":"2.4.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:joshnuss:xml_builder:*:*:*:*:*:*:*:*"],"modules":["'Elixir.XmlBuilder'"],"programFiles":["lib/xml_builder.ex"],"programRoutines":[{"name":"'Elixir.XmlBuilder':generate/1"},{"name":"'Elixir.XmlBuilder':generate/2"},{"name":"'Elixir.XmlBuilder':escape_string/1"},{"name":"'Elixir.XmlBuilder':escape_entity/1"}],"repo":"https://github.com/joshnuss/xml_builder"},{"vendor":"joshnuss","product":"xml_builder","packageName":"joshnuss/xml_builder","packageURL":"pkg:github/joshnuss/xml_builder","defaultStatus":"unaffected","versions":[{"version":"aae31e6e8ac837bcbb8afb816c0d14324b5cfe2b","status":"affected","lessThan":"c3390e2046ec297b3bb8c30d5779cdfd6508c275","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:joshnuss:xml_builder:*:*:*:*:*:*:*:*"],"modules":["'Elixir.XmlBuilder'"],"programFiles":["lib/xml_builder.ex"],"programRoutines":[{"name":"'Elixir.XmlBuilder':generate/1"},{"name":"'Elixir.XmlBuilder':generate/2"},{"name":"'Elixir.XmlBuilder':escape_string/1"},{"name":"'Elixir.XmlBuilder':escape_entity/1"}],"repo":"https://github.com/joshnuss/xml_builder"}],"references":["https://github.com/joshnuss/xml_builder/security/advisories/GHSA-5hjx-8g53-cmvm","https://cna.erlef.org/cves/CVE-2026-47079.html","https://osv.dev/vulnerability/EEF-CVE-2026-47079","https://github.com/joshnuss/xml_builder/commit/c3390e2046ec297b3bb8c30d5779cdfd6508c275"],"weaknesses":["CWE-838"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/47xxx/CVE-2026-47079.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47079","state":"PUBLISHED","datePublished":"2026-08-21T09:52:44.178Z","dateUpdated":"2026-08-21T12:19:47.179Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-05-18T17:28:10.319Z"},"containers":{"cna":{"title":"Round-trip Corruption via Improper Entity Escaping in xml_builder","descriptions":[{"lang":"en","value":"Inappropriate Encoding for Output Context vulnerability in joshnuss xml_builder (XmlBuilder module) allows Content Spoofing, Cross-site Scripting.\n\nThis vulnerability is associated with program files lib/xml_builder.ex and program routines XmlBuilder.generate/1, XmlBuilder.generate/2, XmlBuilder.escape_string/1, XmlBuilder.escape_entity/1.\n\nXmlBuilder.generate/1 does not escape literal & characters in text or attribute values when they are followed by an entity-like token (lt;, gt;, amp;, quot;, apos;). As a result, attacker-supplied input such as &lt;script&gt; is emitted verbatim into the serialized XML rather than being escaped to &amp;lt;script&amp;gt;. When a downstream XML parser later reads the document, it decodes the entity sequences into the literal characters <script>, promoting inert-looking text into real markup. This allows an attacker to bypass upstream filters that block raw < and > characters, injecting markup into any downstream consumer that parses the produced XML and renders the text content in a markup-sensitive context (HTML, SVG, RSS/Atom feeds). Both element text and attribute values are affected.\n\nThis issue affects xml_builder: from 0.0.6 before 2.4.1."}],"affected":[{"vendor":"joshnuss","product":"xml_builder","packageName":"xml_builder","packageURL":"pkg:hex/xml_builder","defaultStatus":"unaffected","versions":[{"version":"0.0.6","status":"affected","lessThan":"2.4.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:joshnuss:xml_builder:*:*:*:*:*:*:*:*"],"modules":["'Elixir.XmlBuilder'"],"programFiles":["lib/xml_builder.ex"],"programRoutines":[{"name":"'Elixir.XmlBuilder':generate/1"},{"name":"'Elixir.XmlBuilder':generate/2"},{"name":"'Elixir.XmlBuilder':escape_string/1"},{"name":"'Elixir.XmlBuilder':escape_entity/1"}],"repo":"https://github.com/joshnuss/xml_builder"},{"vendor":"joshnuss","product":"xml_builder","packageName":"joshnuss/xml_builder","packageURL":"pkg:github/joshnuss/xml_builder","defaultStatus":"unaffected","versions":[{"version":"aae31e6e8ac837bcbb8afb816c0d14324b5cfe2b","status":"affected","lessThan":"c3390e2046ec297b3bb8c30d5779cdfd6508c275","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:joshnuss:xml_builder:*:*:*:*:*:*:*:*"],"modules":["'Elixir.XmlBuilder'"],"programFiles":["lib/xml_builder.ex"],"programRoutines":[{"name":"'Elixir.XmlBuilder':generate/1"},{"name":"'Elixir.XmlBuilder':generate/2"},{"name":"'Elixir.XmlBuilder':escape_string/1"},{"name":"'Elixir.XmlBuilder':escape_entity/1"}],"repo":"https://github.com/joshnuss/xml_builder"}],"references":[{"url":"https://github.com/joshnuss/xml_builder/security/advisories/GHSA-5hjx-8g53-cmvm","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-47079.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-47079","tags":["related"]},{"url":"https://github.com/joshnuss/xml_builder/commit/c3390e2046ec297b3bb8c30d5779cdfd6508c275","tags":["patch"]}],"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:N/VA:N/SC:N/SI:L/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-838","description":"CWE-838 Inappropriate Encoding for Output Context","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-08-21T09:52:44.178Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:joshnuss:xml_builder:*:*:*:*:*:*:*:*","versionEndExcluding":"2.4.1","versionStartIncluding":"0.0.6","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Joshua Nussbaum"},{"lang":"en","type":"coordinator","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-120","descriptions":[{"lang":"en","value":"CAPEC-120 Double Encoding"}]}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/joshnuss/xml_builder/security/advisories/GHSA-5hjx-8g53-cmvm","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-21T12:17:52.012230Z","id":"CVE-2026-47079","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-21T12:19:47.179Z"}}]}}}