freescout-help-desk FreeScout up to 1.8.224 Mailbox Signature /uploads/upload stripDangerousTags cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, has been found in freescout-help-desk FreeScout up to 1.8.224. This affects the function Helper::stripDangerousTags of the file /uploads/upload of the component Mailbox Signature. Performing a manipulation results in cross site scripting. This vulnerability is reported as CVE-2026-62854. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in freescout-help-desk FreeScout up to 1.8.224. This affects the function Helper::stripDangerousTags of the file /uploads/upload of the component Mailbox Signature. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. The summary by CVE is:

FreeScout is a self-hosted help desk and shared mailbox. Prior to 1.8.225, a user who can edit a mailbox signature can combine a scriptable file uploaded through /uploads/upload with nested tag fragments that bypass Helper::stripDangerousTags(). The resulting external script is served from the same origin, so the script-src 'self' policy permits it when another user opens the affected mailbox reply editor or new-ticket page. The script executes with the victim's FreeScout privileges and can read visible data and perform same-origin actions. This issue is fixed in version 1.8.225.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-62854 since 07/14/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 1.8.225 eliminates this vulnerability.

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Productinfo

Vendor

• freescout-help-desk

Name

• FreeScout

Version

• 1.8.224

Website

• Product: https://github.com/freescout-help-desk/freescout/

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