CVE-2026-104828

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-104828", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-10-02T14:17:09.335Z", "datePublished": "2026-10-15T18:36:49.613Z", "dateUpdated": "2026-10-21T01:04:51.279Z"}, "containers": {"cna": {"title": "HtmlUnit Neko: Mutation XSS (mXSS) in HTMLWriterFilter - TEXTAREA/TITLE entity decode without re-encode", "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "lang": "en", "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785"}, {"name": "https://github.com/HtmlUnit/htmlunit-neko/commit/c165891e0753aef3e05f5daa6250d3e8d4ada3c0", "tags": ["x_refsource_MISC"], "url": "https://github.com/HtmlUnit/htmlunit-neko/commit/c165891e0753aef3e05f5daa6250d3e8d4ada3c0"}, {"name": "https://github.com/HtmlUnit/htmlunit-neko/releases/tag/5.4.0", "tags": ["x_refsource_MISC"], "url": "https://github.com/HtmlUnit/htmlunit-neko/releases/tag/5.4.0"}], "affected": [{"vendor": "HtmlUnit", "product": "htmlunit-neko", "versions": [{"version": "< 5.4.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-15T18:39:13.508Z"}, "descriptions": [{"lang": "en", "value": "HtmlUnit Neko is an HtmlUnit adaptation of NekoHTML. Prior to 5.4.0, HTMLWriterFilter writes decoded TEXTAREA and TITLE character content without entity encoding because both elements are treated as special content. During a parse-and-serialize round trip, entity references inside these escapable raw-text elements are decoded by the parser and then emitted as raw markup by printCharacters(), changing the document's semantics. Applications that use htmlunit-neko in an HTML sanitizer, content filter, or other parse-transform-serialize pipeline can therefore turn attacker-controlled encoded text into executable markup when the output is rendered by a browser. This issue is fixed in version 5.4.0."}], "source": {"advisory": "GHSA-39xg-prhf-8785", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-10-21T01:04:22.177553Z", "id": "CVE-2026-104828", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-21T01:04:51.279Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-104828", "role": "CISA Coordinator", "options": [{"Exploitation": "poc"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-21T01:04:22.177553Z"}}}], "references": [{"url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785", "tags": ["exploit"]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-21T01:04:41.920Z"}}], "cna": {"title": "HtmlUnit Neko: Mutation XSS (mXSS) in HTMLWriterFilter - TEXTAREA/TITLE entity decode without re-encode", "source": {"advisory": "GHSA-39xg-prhf-8785", "discovery": "UNKNOWN"}, "metrics": [{"cvssV3_1": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.2, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}], "affected": [{"vendor": "HtmlUnit", "product": "htmlunit-neko", "versions": [{"status": "affected", "version": "< 5.4.0"}]}], "references": [{"url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785", "name": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785", "tags": ["x_refsource_CONFIRM"]}, {"url": "https://github.com/HtmlUnit/htmlunit-neko/commit/c165891e0753aef3e05f5daa6250d3e8d4ada3c0", "name": "https://github.com/HtmlUnit/htmlunit-neko/commit/c165891e0753aef3e05f5daa6250d3e8d4ada3c0", "tags": ["x_refsource_MISC"]}, {"url": "https://github.com/HtmlUnit/htmlunit-neko/releases/tag/5.4.0", "name": "https://github.com/HtmlUnit/htmlunit-neko/releases/tag/5.4.0", "tags": ["x_refsource_MISC"]}], "descriptions": [{"lang": "en", "value": "HtmlUnit Neko is an HtmlUnit adaptation of NekoHTML. Prior to 5.4.0, HTMLWriterFilter writes decoded TEXTAREA and TITLE character content without entity encoding because both elements are treated as special content. During a parse-and-serialize round trip, entity references inside these escapable raw-text elements are decoded by the parser and then emitted as raw markup by printCharacters(), changing the document's semantics. Applications that use htmlunit-neko in an HTML sanitizer, content filter, or other parse-transform-serialize pipeline can therefore turn attacker-controlled encoded text into executable markup when the output is rendered by a browser. This issue is fixed in version 5.4.0."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-79", "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-10-15T18:39:13.508Z"}}}, "cveMetadata": {"cveId": "CVE-2026-104828", "state": "PUBLISHED", "dateUpdated": "2026-10-21T01:04:51.279Z", "dateReserved": "2026-10-02T14:17:09.335Z", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "datePublished": "2026-10-15T18:36:49.613Z", "assignerShortName": "GitHub_M"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "htmlunit-neko", "vendor": "HtmlUnit", "versions": [{"status": "affected", "version": "< 5.4.0"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "HtmlUnit Neko is an HtmlUnit adaptation of NekoHTML. Prior to 5.4.0, HTMLWriterFilter writes decoded TEXTAREA and TITLE character content without entity encoding because both elements are treated as special content. During a parse-and-serialize round trip, entity references inside these escapable raw-text elements are decoded by the parser and then emitted as raw markup by printCharacters(), changing the document's semantics. Applications that use htmlunit-neko in an HTML sanitizer, content filter, or other parse-transform-serialize pipeline can therefore turn attacker-controlled encoded text into executable markup when the output is rendered by a browser. This issue is fixed in version 5.4.0."}], "id": "CVE-2026-104828", "lastModified": "2026-10-21T01:17:19.770", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.2, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 2.7, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-104828", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-21T01:04:22.177553Z", "version": "2.0.3"}}]}, "published": "2026-10-15T19:17:15.083", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/HtmlUnit/htmlunit-neko/commit/c165891e0753aef3e05f5daa6250d3e8d4ada3c0"}, {"source": "security-advisories@github.com", "url": "https://github.com/HtmlUnit/htmlunit-neko/releases/tag/5.4.0"}, {"source": "security-advisories@github.com", "url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/HtmlUnit/htmlunit-neko/security/advisories/GHSA-39xg-prhf-8785"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,5.4.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "product": "htmlunit-neko", "vendor": "htmlunit"}], "created": "2026-10-16T17:45:14.080378+00:00", "updated": "2026-10-19T14:01:01.250292+00:00", "vendors": ["htmlunit", "htmlunit$PRODUCT$htmlunit-neko"]}