CVE-2026-40496Public exploitNetwork attack vector

Unauthenticated attachment disclosure via predictable tokens

Published Apr 21, 2026 · Updated Apr 21, 2026

Information disclosure in FreeScout before 1.8.213 allows remote attackers to download private attachments with forged tokens. Attachment::getToken concatenates the application key, sequential attachment ID, and brute-forceable size before hashing the result with MD5. No account is required, and successful token guesses expose private attachments across mailboxes and customers.

CVSS severity9.1
Critical
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in FreeScout before 1.8.213 allows remote attackers to download private attachments with forged tokens. Attachment::getToken concatenates the application key, sequential attachment ID, and brute-forceable size before hashing the result with MD5. No account is required, and successful token guesses expose private attachments across mailboxes and customers.

The record

CVE
CVE-2026-40496
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
FreeScout
Product
FreeScout
Classifications
CWE-330, CWE-340, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.8.213

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeScout · FreeScoutversion=< 1.8.213

Published CVSS scores

8.8GitHub, Inc.CVSS: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
9.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-330Use of Insufficiently Random Values
CWE-340Generation of Predictable Numbers or Identifiers
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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