CVE-2026-40496

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 66% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
72(Attend)
EG Risk 72/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

April 21, 2026

Last Modified

April 23, 2026

Advisory Details (3)

Auto-updated Aug 1, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

Predictable Attachment Token Allows Unauthenticated Private File Download via Brute Force · Advisory · freescout-help-desk/freescout · GitHub

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-2783-wxmm-wmwr
github_release Patch Available

1.8.213

Patch available: freescout-help-desk/freescout 1.8.213

https://github.com/freescout-help-desk/freescout/releases/tag/1.8.213
github_commit Patch Available

commit dbdf8f2260b4 (freescout-help-desk/freescout)

Patch available: freescout-help-desk/freescout 1.8.213 (contains commit dbdf8f2260b4)

https://github.com/freescout-help-desk/freescout/commit/dbdf8f2260b43a21818255c70f0b61b9de9cd555

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 157 total refreshes for this CVE.

  1. 2026-09-15 03:11 UTCEPSS rescore
  2. 2026-09-13 16:47 UTCEPSS rescore
  3. 2026-09-12 15:01 UTCEPSS rescore
  4. 2026-09-11 14:53 UTCEPSS rescore
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  11. 2026-09-02 14:31 UTCOSV refresh
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  1. 2026-08-17 13:47 UTCEPSS rescore
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  3. 2026-08-16 06:21 UTCEG score recompute
  4. 2026-08-16 02:14 UTCEPSS rescore
  5. 2026-08-15 02:24 UTCEG score recompute
  6. 2026-08-15 01:30 UTCEPSS rescore
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  8. 2026-08-13 22:00 UTCEPSS rescore
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  10. 2026-08-12 13:51 UTCEPSS rescore
  11. 2026-08-11 16:53 UTCEG score recompute
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  13. 2026-08-11 02:28 UTCEG score recompute
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  15. 2026-08-09 16:43 UTCEG score recompute
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  18. 2026-08-08 16:37 UTCEPSS rescore
  19. 2026-08-07 17:08 UTCEG score recompute
  20. 2026-08-06 17:27 UTCEG score recompute
  21. 2026-08-06 13:46 UTCEPSS rescore
  22. 2026-08-05 23:12 UTCEG score recompute
  23. 2026-08-05 19:17 UTCEPSS rescore
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:38 UTCEPSS rescore
  26. 2026-08-03 21:25 UTCEG score recompute
  27. 2026-08-03 10:36 UTCEPSS rescore
  28. 2026-08-02 12:51 UTCEG score recompute
  29. 2026-08-02 02:27 UTCEPSS rescore
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  40. 2026-07-24 14:17 UTCEPSS rescore
  41. 2026-07-23 14:18 UTCEPSS rescore
  42. 2026-07-23 14:18 UTCEPSS rescore
  43. 2026-07-23 03:11 UTCEG score recompute
  44. 2026-07-22 14:08 UTCEPSS rescore
  45. 2026-07-21 15:24 UTCEPSS rescore
  46. 2026-07-20 17:32 UTCOSV refresh
  47. 2026-07-20 17:08 UTCEPSS rescore
  48. 2026-07-19 14:31 UTCEPSS rescore
  49. 2026-07-19 02:29 UTCEPSS rescore
  50. 2026-07-18 10:04 UTCEPSS rescore
  51. 2026-07-16 17:03 UTCEPSS rescore
  52. 2026-07-15 16:57 UTCEPSS rescore
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  60. 2026-07-09 19:10 UTCEPSS rescore
  61. 2026-07-08 15:15 UTCEPSS rescore
  62. 2026-07-07 13:46 UTCEPSS rescore
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  65. 2026-07-06 02:23 UTCEPSS rescore
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  67. 2026-07-05 02:30 UTCEPSS rescore
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  70. 2026-06-30 23:22 UTCEPSS rescore
  71. 2026-06-29 14:06 UTCEPSS rescore
  72. 2026-06-28 14:07 UTCEPSS rescore
  73. 2026-06-28 04:56 UTCEPSS rescore
  74. 2026-06-27 03:08 UTCEPSS rescore
  75. 2026-06-25 13:49 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-40496?
CVE-2026-40496 is a critical vulnerability published on April 21, 2026. 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(APPKEY + attachmentid + size). Since attachment_id is sequential and size can be brute-forced in a small range, an…
When was CVE-2026-40496 disclosed?
CVE-2026-40496 was first published in the National Vulnerability Database on April 21, 2026, with the most recent update on April 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40496 actively exploited?
CVE-2026-40496 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.1% of all scored CVEs.
What is the CVSS score of CVE-2026-40496?
CVE-2026-40496 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-40496?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40496, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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