# CVE-2026-62854: FreeScout stored XSS in mailbox signature via nested tag bypass

Source: https://junglewise.ai/threats/cve-2026-62854-freescout-is-a-self-hosted-help-desk-and-shared-mailbox-prior-to  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-62854 · Severity: high · CVSS 7.6 · Published 2026-11-06

FreeScout is a self-hosted help desk and shared mailbox platform. A user with mailbox signature edit permissions can inject malicious scripts by uploading files and using nested HTML tags to bypass the application's tag-stripping protection. When another user views the affected mailbox's reply editor or new-ticket page, the injected script executes with their privileges, allowing the attacker to steal data or perform actions on their behalf.

Technologies: [FreeScout](https://junglewise.ai/threats/technologies/freescout-freescout). Vendors: [FreeScout](https://junglewise.ai/threats/vendors/freescout).

## Quick answers

**Is CVE-2026-62854 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-62854 being exploited in the wild.

**How severe is CVE-2026-62854?** High severity, with a CVSS score of 7.6, published 6 November 2026.

**Which products and versions are affected?** FreeScout prior to 1.8.225.

**Is there a fix for CVE-2026-62854?** Yes: fixed in 1.8.225. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-62854 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-62854?** Check whether you run FreeScout at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.8.225

## Technical details

A stored cross-site scripting vulnerability exists in FreeScout's Helper::stripDangerousTags() function, which fails to recursively strip nested dangerous HTML tags from mailbox signatures. An attacker with mailbox signature edit permissions can combine a scriptable file uploaded via /uploads/upload with nested tag fragments to bypass the filter. The resulting script is served from the same origin and permitted by the script-src 'self' Content Security Policy, executing with the victim's privileges when they open the mailbox reply editor or new-ticket creation page.

## Affected products

- FreeScout FreeScout prior to 1.8.225

## Timeline

- 2026-11-06: disclosed
- 2026-11-06: patched: Fix implemented via improved stripDangerousTags() with recursive removal of nested tags

## References

- [https://github.com/freescout-help-desk/freescout/commit/315ad05f73886649cb8bc2c014dd74b62cc28502](https://github.com/freescout-help-desk/freescout/commit/315ad05f73886649cb8bc2c014dd74b62cc28502)
- [https://github.com/freescout-help-desk/freescout/commit/7f6a5042c1326ceaf511f13982178dce036cedbe](https://github.com/freescout-help-desk/freescout/commit/7f6a5042c1326ceaf511f13982178dce036cedbe)

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