CVE-2026-40497

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{"affected": [{"affectedData": [{"product": "freescout", "vendor": "freescout-help-desk", "versions": [{"status": "affected", "version": "< 1.8.213"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:freescout:freescout:*:*:*:*:*:*:*:*", "matchCriteriaId": "EA97ED0A-4886-4583-9D20-47BE39C40B01", "versionEndExcluding": "1.8.213", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, FreeScout's `Helper::stripDangerousTags()` removes `<script>`, `<form>`, `<iframe>`, `<object>` but does NOT strip `<style>` tags. The mailbox signature field is saved via POST /mailbox/settings/{id} and later rendered unescaped via `{!! $conversation->getSignatureProcessed([], true) !!}` in conversation views. CSP allows `style-src * 'self' 'unsafe-inline'`, so injected inline styles execute freely. An attacker with access to mailbox settings (admin or agent with mailbox permission) can inject CSS attribute selectors to exfiltrate the CSRF token of any agent/admin who views a conversation in that mailbox. With the CSRF token, the attacker can perform any state-changing action as the victim (create admin accounts, change email/password, etc.) \u2014 privilege escalation from agent to admin. This is the result of an incomplete fix of GHSA-jqjf-f566-485j. That advisory reported XSS via mailbox signature. The fix applied `Helper::stripDangerousTags()` to the signature before saving. However, `stripDangerousTags()` only removes `script`, `form`, `iframe`, and `object` tags \u2014 it does NOT strip `<style>` tags, leaving CSS injection possible. Version 1.8.213 contains an updated fix."}, {"lang": "es", "value": "FreeScout es un help desk autoalojado gratuito y un buz\u00f3n compartido. Antes de la versi\u00f3n 1.8.213, Helper::stripDangerousTags() de FreeScout elimina \u201c[script_tag]\u201d, \u201c[form]\u201d, \u201c[iframe_tag]\u201d, \u201c[object_tag]\u201d pero NO elimina las etiquetas \u201c[style]\u201d. El campo de firma del buz\u00f3n se guarda a trav\u00e9s de POST /mailbox/settings/{id} y luego se renderiza sin escapar a trav\u00e9s de {!! $conversation -> getSignatureProcessed([], true) !!} en las vistas de conversaci\u00f3n. CSP permite style-src * \u2019self\u2019 \u2019unsafe-inline\u2019, por lo que los estilos en l\u00ednea inyectados se ejecutan libremente. Un atacante con acceso a la configuraci\u00f3n del buz\u00f3n (administrador o agente con permiso de buz\u00f3n) puede inyectar selectores de atributos CSS para exfiltrar el token CSRF de cualquier agente/administrador que vea una conversaci\u00f3n en ese buz\u00f3n. Con el token CSRF, el atacante puede realizar cualquier acci\u00f3n que cambie el estado como la v\u00edctima (crear cuentas de administrador, cambiar correo electr\u00f3nico/contrase\u00f1a, etc.) - escalada de privilegios de agente a administrador. Esto es el resultado de una correcci\u00f3n incompleta de GHSA-jqjf-f566-485j. Esa advertencia inform\u00f3 XSS a trav\u00e9s de la firma del buz\u00f3n. La correcci\u00f3n aplic\u00f3 Helper::stripDangerousTags() a la firma antes de guardar. Sin embargo, stripDangerousTags() solo elimina las etiquetas script, form, iframe y object - NO elimina las etiquetas \u201c[style]\u201d, dejando posible la inyecci\u00f3n CSS. La versi\u00f3n 1.8.213 contiene una correcci\u00f3n actualizada."}], "id": "CVE-2026-40497", "lastModified": "2026-11-11T23:10:00.263", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "HIGH", "scope": "CHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 1.7, "impactScore": 5.8, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-40497", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-04-21T13:25:17.184928Z", "version": "2.0.3"}}]}, "published": "2026-04-21T03:16:08.403", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/freescout-help-desk/freescout/commit/5aa8d633216f65995e80a7d4a921b784acc94df4"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213"}, {"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-fh99-wr77-pxq3"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Vendor Advisory"], "url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-fh99-wr77-pxq3"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-79"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.8.213)"}}], "enrichment": {"confidence": 98.0, "confidence_source": "matching", "scores": [{"score": 98.0, "source": "matching"}]}, "original": {"product": "freescout", "source": "cna", "vendor": "freescout-help-desk"}, "product": "freescout", "vendor": "freescout_helpdesk"}], "analysis": {"en": {"generated_at": "2026-04-21T15:29:15.084276+00:00", "value": {"mitigation_remediation": ["Update FreeScout to version 1.8.213 or later, which sanitizes the signature field during save.", "Limit mailbox settings modification rights to administrators only; remove this permission from agents if unnecessary.", "Audit existing mailbox signatures and delete any embedded <style> tags or inline CSS; reset them to plain text or safe HTML.", "Enable an audit trail for signature changes so that any unauthorized modifications can be detected and rolled back."], "summary": {"action": "Patch Immediately", "impact": "Privilege Escalation via CSRF Token Theft"}, "threat_synthesis": {"affected_systems": "The vulnerability affects all FreeScout installations running a version older than 1.8.213. The issue is present in the freescout-help-desk:freescout product before this release and was fully addressed in the 1.8.213 update.", "description_and_impact": "FreeScout fails to strip <style> tags from mailbox signatures. When a signature containing inline CSS is stored, it is rendered with unsafe HTML, allowing attackers who can edit mailbox settings to inject CSS selectors that read the CSRF token of any user who views a conversation. The stolen token enables the attacker to perform state\u2011changing actions as that user, such as creating administrative accounts or changing passwords, effectively escalating from an agent to an administrator. This flaw is categorized as a stored cross\u2011site scripting vulnerability (CWE\u201179).", "risk_and_exploitability": "The CVSS base score of 8.1 indicates a high severity risk, although the EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, suggesting no publicly documented exploitation yet. Exploitation requires authenticated access to mailbox settings, meaning the attacker must be a user with mailbox management privileges (admin or agent). Once the privilege escalation occurs, any authenticated action can be abused. Because the flaw relies on stored data, an attacker could persist the exploit through repeated sessions but would need to maintain credentials to inject the malicious signature."}}}}, "created": "2026-04-21T03:30:26.147210+00:00", "updated": "2026-04-21T15:37:55.176313+00:00", "vendors": ["freescout_helpdesk", "freescout_helpdesk$PRODUCT$freescout"]}