Paper/Archive/CVE-2026-40496

CVE-2026-40496

freescout-help-desk freescout — FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force

EPSS 0.4%public exploit CVSS 9.1

critical.is priorityof 100

CVSS 9.1 (NVD)9.1 / 10 × 3027.3 Not in CISA KEV+300.0 EPSS percentile 34.6.346 × 206.9 Exploit: SSVC poc+1010.0 SSVC exploitation: poc+100.0

Description · from the CVE record

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential and size can be brute-forced in a small range, an unauthenticated attacker can forge valid tokens and download any private attachment without credentials. Version 1.8.213 fixes the issue.

Affected

ProductAffectedFixed inSource

freescout< 1.8.213–CNA

Scores by source

NVD9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

GitHub_M (CNA)8.8CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:P

CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: partial

References

refgithub.com/freescout-help-desk/freescout/security/advisories/GHSA-2783-wxmm-wmwr refgithub.com/freescout-help-desk/freescout/commit/dbdf8f2260b43a21818255c70f0b61b9de9cd555 refgithub.com/freescout-help-desk/freescout/releases/tag/1.8.213