CVE-2026-22028

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-22028", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-01-05T22:30:38.718Z", "datePublished": "2026-01-08T14:16:22.461Z", "dateUpdated": "2026-01-08T15:55:06.321Z"}, "containers": {"cna": {"title": "Preact has JSON VNode Injection issue", "problemTypes": [{"descriptions": [{"cweId": "CWE-843", "lang": "en", "description": "CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')", "type": "CWE"}]}], "metrics": [{"cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 7.2, "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U", "version": "4.0"}}], "references": [{"name": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m"}], "affected": [{"vendor": "preactjs", "product": "preact", "versions": [{"version": ">= 10.26.5, < 10.26.10", "status": "affected"}, {"version": ">= 10.27.0, < 10.27.3", "status": "affected"}, {"version": ">= 10.28.0, < 10.28.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-01-08T14:17:41.614Z"}, "descriptions": [{"lang": "en", "value": "Preact, a lightweight web development framework, JSON serialization protection to prevent Virtual DOM elements from being constructed from arbitrary JSON. A regression introduced in Preact 10.26.5 caused this protection to be softened. In applications where values from JSON payloads are assumed to be strings and passed unmodified to Preact as children, a specially-crafted JSON payload could be constructed that would be incorrectly treated as a valid VNode. When this chain of failures occurs it can result in HTML injection, which can allow arbitrary script execution if not mitigated by CSP or other means. Applications using affected Preact versions are vulnerable if they meet all of the following conditions: first, pass unmodified, unsanitized values from user-modifiable data sources (APIs, databases, local storage, etc.) directly into the render tree; second assume these values are strings but the data source could return actual JavaScript objects instead of JSON strings; and third, the data source either fails to perform type sanitization AND blindly stores/returns raw objects interchangeably with strings, OR is compromised (e.g., poisoned local storage, filesystem, or database). Versions 10.26.10, 10.27.3, and 10.28.2 patch the issue. The patch versions restore the previous strict equality checks that prevent JSON-parsed objects from being treated as valid VNodes. Other mitigations are available for those who cannot immediately upgrade. Validate input types, cast or validate network data, sanitize external data, and use Content Security Policy (CSP)."}], "source": {"advisory": "GHSA-36hm-qxxp-pg3m", "discovery": "UNKNOWN"}}, "adp": [{"references": [{"url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-01-08T14:52:00.716865Z", "id": "CVE-2026-22028", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-08T15:55:06.321Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-22028", "role": "CISA Coordinator", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-01-08T14:52:00.716865Z"}}}], "references": [{"url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m", "tags": ["exploit"]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-08T14:52:03.379Z"}}], "cna": {"title": "Preact has JSON VNode Injection issue", "source": {"advisory": "GHSA-36hm-qxxp-pg3m", "discovery": "UNKNOWN"}, "metrics": [{"cvssV4_0": {"version": "4.0", "baseScore": 7.2, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH"}}], "affected": [{"vendor": "preactjs", "product": "preact", "versions": [{"status": "affected", "version": ">= 10.26.5, < 10.26.10"}, {"status": "affected", "version": ">= 10.27.0, < 10.27.3"}, {"status": "affected", "version": ">= 10.28.0, < 10.28.2"}]}], "references": [{"url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m", "name": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m", "tags": ["x_refsource_CONFIRM"]}], "descriptions": [{"lang": "en", "value": "Preact, a lightweight web development framework, JSON serialization protection to prevent Virtual DOM elements from being constructed from arbitrary JSON. A regression introduced in Preact 10.26.5 caused this protection to be softened. In applications where values from JSON payloads are assumed to be strings and passed unmodified to Preact as children, a specially-crafted JSON payload could be constructed that would be incorrectly treated as a valid VNode. When this chain of failures occurs it can result in HTML injection, which can allow arbitrary script execution if not mitigated by CSP or other means. Applications using affected Preact versions are vulnerable if they meet all of the following conditions: first, pass unmodified, unsanitized values from user-modifiable data sources (APIs, databases, local storage, etc.) directly into the render tree; second assume these values are strings but the data source could return actual JavaScript objects instead of JSON strings; and third, the data source either fails to perform type sanitization AND blindly stores/returns raw objects interchangeably with strings, OR is compromised (e.g., poisoned local storage, filesystem, or database). Versions 10.26.10, 10.27.3, and 10.28.2 patch the issue. The patch versions restore the previous strict equality checks that prevent JSON-parsed objects from being treated as valid VNodes. Other mitigations are available for those who cannot immediately upgrade. Validate input types, cast or validate network data, sanitize external data, and use Content Security Policy (CSP)."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-843", "description": "CWE-843: Access of Resource Using Incompatible Type ('Type Confusion')"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-01-08T14:17:41.614Z"}}}, "cveMetadata": {"cveId": "CVE-2026-22028", "state": "PUBLISHED", "dateUpdated": "2026-01-08T15:55:06.321Z", "dateReserved": "2026-01-05T22:30:38.718Z", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "datePublished": "2026-01-08T14:16:22.461Z", "assignerShortName": "GitHub_M"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"product": "preact", "vendor": "preactjs", "versions": [{"status": "affected", "version": ">= 10.26.5, < 10.26.10"}, {"status": "affected", "version": ">= 10.27.0, < 10.27.3"}, {"status": "affected", "version": ">= 10.28.0, < 10.28.2"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:preactjs:preact:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "1DDBA9E9-C9AF-4A0C-A2B7-E2EA43E9DF0E", "versionEndExcluding": "10.26.10", "versionStartIncluding": "10.26.5", "vulnerable": true}, {"criteria": "cpe:2.3:a:preactjs:preact:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "0E2DB796-AF49-4BCD-9D92-FDF44B81BA49", "versionEndExcluding": "10.27.3", "versionStartIncluding": "10.27.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:preactjs:preact:*:*:*:*:*:node.js:*:*", "matchCriteriaId": "FD739420-5F94-401E-8D6E-048B9EE0AAC4", "versionEndExcluding": "10.28.2", "versionStartIncluding": "10.28.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Preact, a lightweight web development framework, JSON serialization protection to prevent Virtual DOM elements from being constructed from arbitrary JSON. A regression introduced in Preact 10.26.5 caused this protection to be softened. In applications where values from JSON payloads are assumed to be strings and passed unmodified to Preact as children, a specially-crafted JSON payload could be constructed that would be incorrectly treated as a valid VNode. When this chain of failures occurs it can result in HTML injection, which can allow arbitrary script execution if not mitigated by CSP or other means. Applications using affected Preact versions are vulnerable if they meet all of the following conditions: first, pass unmodified, unsanitized values from user-modifiable data sources (APIs, databases, local storage, etc.) directly into the render tree; second assume these values are strings but the data source could return actual JavaScript objects instead of JSON strings; and third, the data source either fails to perform type sanitization AND blindly stores/returns raw objects interchangeably with strings, OR is compromised (e.g., poisoned local storage, filesystem, or database). Versions 10.26.10, 10.27.3, and 10.28.2 patch the issue. The patch versions restore the previous strict equality checks that prevent JSON-parsed objects from being treated as valid VNodes. Other mitigations are available for those who cannot immediately upgrade. Validate input types, cast or validate network data, sanitize external data, and use Content Security Policy (CSP)."}, {"lang": "es", "value": "Preact, un framework ligero de desarrollo web, protecci\u00f3n de serializaci\u00f3n JSON para evitar que los elementos del DOM Virtual se construyan a partir de JSON arbitrario. Una regresi\u00f3n introducida en Preact 10.26.5 hizo que esta protecci\u00f3n se suavizara. En aplicaciones donde se asume que los valores de las cargas \u00fatiles JSON son cadenas y se pasan sin modificar a Preact como hijos, se podr\u00eda construir una carga \u00fatil JSON especialmente dise\u00f1ada que ser\u00eda tratada incorrectamente como un VNode v\u00e1lido. Cuando esta cadena de fallos ocurre, puede resultar en inyecci\u00f3n HTML, lo que puede permitir la ejecuci\u00f3n arbitraria de scripts si no se mitiga mediante CSP u otros medios. Las aplicaciones que utilizan versiones afectadas de Preact son vulnerables si cumplen todas las siguientes condiciones: primero, pasan valores sin modificar y sin sanear de fuentes de datos modificables por el usuario (APIs, bases de datos, almacenamiento local, etc.) directamente al \u00e1rbol de renderizado; segundo, asumen que estos valores son cadenas pero la fuente de datos podr\u00eda devolver objetos JavaScript reales en lugar de cadenas JSON; y tercero, la fuente de datos o bien no realiza la sanitizaci\u00f3n de tipos Y almacena/devuelve ciegamente objetos sin procesar indistintamente con cadenas, O est\u00e1 comprometida (p. ej., almacenamiento local, sistema de archivos o base de datos envenenados). Las versiones 10.26.10, 10.27.3 y 10.28.2 aplican un parche al problema. Las versiones del parche restauran las comprobaciones de igualdad estricta anteriores que evitan que los objetos analizados por JSON sean tratados como VNodes v\u00e1lidos. Otras mitigaciones est\u00e1n disponibles para aquellos que no pueden actualizar de inmediato. Validar tipos de entrada, convertir o validar datos de red, sanear datos externos y usar la Pol\u00edtica de Seguridad de Contenido (CSP)."}], "id": "CVE-2026-22028", "lastModified": "2026-06-17T10:19:23.103", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.7, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.2, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "UNREPORTED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-22028", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-01-08T14:52:00.716865Z", "version": "2.0.3"}}]}, "published": "2026-01-08T15:15:44.853", "references": [{"source": "security-advisories@github.com", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "url": "https://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-843"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "preact: Preact: Arbitrary script execution via JSON serialization protection bypass", "id": "2427941", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2427941"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.1", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L", "status": "draft"}, "cwe": "CWE-843", "details": ["A flaw was found in Preact, a lightweight web development framework. A security regression allows an attacker to bypass JSON serialization protection, leading to HTML injection. This vulnerability arises when applications process unsanitized data from external sources, allowing malicious JSON to be interpreted as valid user interface elements. If exploited, this could enable arbitrary script execution, potentially compromising user data or system integrity."], "name": "CVE-2026-22028", "package_state": [{"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/cluster-logging-operator-bundle", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/cluster-logging-rhel9-operator", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/eventrouter-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/fluentd-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/log-file-metric-exporter-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/logging-view-plugin-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:logging:5", "fix_state": "Affected", "package_name": "openshift-logging/vector-rhel9", "product_name": "Logging Subsystem for Red Hat OpenShift"}, {"cpe": "cpe:/a:redhat:openshift_lightspeed", "fix_state": "Affected", "package_name": "openshift-lightspeed/lightspeed-console-plugin-rhel9", "product_name": "OpenShift Lightspeed"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Affected", "package_name": "ansible-automation-platform-26/gateway-rhel9", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/a:redhat:ansible_automation_platform:2", "fix_state": "Affected", "package_name": "automation-platform-ui", "product_name": "Red Hat Ansible Automation Platform 2"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "gjs", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "mozjs60", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "gjs", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "polkit", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-dashboard-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-mod-arch-gen-ai-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-mod-arch-model-registry-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift4/ose-agent-installer-ui-rhel9", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:amq_streams:2", "fix_state": "Affected", "package_name": "com.github.streamshub-console", "product_name": "streams for Apache Kafka 2"}, {"cpe": "cpe:/a:redhat:amq_streams:3", "fix_state": "Affected", "package_name": "com.github.streamshub-console", "product_name": "streams for Apache Kafka 3"}], "public_date": "2026-01-08T14:16:22Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-22028\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-22028\nhttps://github.com/preactjs/preact/security/advisories/GHSA-36hm-qxxp-pg3m"], "threat_severity": "Important"}

{"analysis": {"en": {"generated_at": "2026-04-18T07:41:09.217663+00:00", "value": {"mitigation_remediation": ["Upgrade Preact to version 10.26.10, 10.27.3, or 10.28.2 or newer.", "Enable a strong Content\u2011Security\u2011Policy that blocks inline scripts and restricts script sources.", "Validate and sanitize all external input before passing it to Preact: ensure values are strings, and reject or convert object payloads."], "summary": {"action": "Immediate Patch", "impact": "Cross\u2011Site Scripting via JSON VNode injection leading to arbitrary script execution"}, "threat_synthesis": {"affected_systems": "The Preact library, developed by preactjs, is affected. Versions beginning with 10.26.5 up to but not including 10.28.2 are vulnerable. The fix is applied in 10.26.10, 10.27.3, and 10.28.2. Any application using Preact within that range and feeding unvalidated JSON payloads into the render tree is at risk.", "description_and_impact": "Preact implements JSON serialization protection to guard against virtual\u2011dom elements constructed from arbitrary JSON. A regression introduced in version 10.26.5 relaxed that protection, allowing a specially crafted JSON payload to be interpreted as a valid VNode. If an application renders unsanitized values from user\u2011modifiable sources directly as children, the flaw can inject HTML that is then interpreted by the browser, enabling arbitrary script execution. The vulnerability is a type\u2011confusion flaw (CWE\u2011843) and results in a classic XSS vector.", "risk_and_exploitability": "The CVSS score of 7.2 indicates high severity. The EPSS score is below 1\u202f%, implying a low current exploitation probability. The vulnerability is not listed in CISA's KEV catalogue. Exploitation requires an attacker to supply or influence user\u2011modifiable data (e.g., via APIs, databases, or local storage) that contains objects instead of plain strings and is directly rendered by Preact. If all conditions are met, an attacker can inject arbitrary HTML and scripts, compromising confidentiality, integrity, and availability of the affected application."}}}}, "created": "2026-04-18T07:45:24.982399+00:00", "updated": "2026-04-18T07:45:24.982410+00:00", "vendors": []}