CVE-2026-40569Public exploitNetwork attack vector

Email exfiltration via unrestricted mailbox attribute assignment

Published Apr 21, 2026 · Updated Apr 21, 2026

Mass assignment in FreeScout before 1.8.213 allows remote authenticated users to silently copy outgoing mailbox email. The connectionIncomingSave and connectionOutgoingSave handlers pass every request field to Mailbox fill, allowing unrelated fillable attributes such as auto_bcc to be persisted. Administrator access and a valid session are required; a crafted save request can persistently BCC every later outgoing message without appearing on the connection settings page.

CVSS severity9.0
Critical
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Mass assignment in FreeScout before 1.8.213 allows remote authenticated users to silently copy outgoing mailbox email. The connectionIncomingSave and connectionOutgoingSave handlers pass every request field to Mailbox fill, allowing unrelated fillable attributes such as auto_bcc to be persisted. Administrator access and a valid session are required; a crafted save request can persistently BCC every later outgoing message without appearing on the connection settings page.

The record

CVE
CVE-2026-40569
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
FreeScout
Product
FreeScout
Classifications
CWE-915, CWE-284, T1114
Attack vector
network
Privileges
admin

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 privilegesadmin

What is affected?

FreeScout · FreeScoutversion=< 1.8.213

Published CVSS scores

9.0GitHubCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:L

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-915Improperly Controlled Modification of Dynamically-Determined Object Attributes
CWE-284Improper Access Control
T1114Email Collection

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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