CVE-2026-47123Public exploitNetwork attack vector

Agent impersonation via missing notification-reply HMAC

Published May 29, 2026 · Updated May 29, 2026

Authentication bypass in FreeScout before 1.8.220 allows remote attackers to impersonate agents and send forged replies to customers. FetchEmails processMessage() trusts thread and user identifiers from notification-reply Message-IDs without verifying an APP_KEY-derived HMAC. Exploitation requires a valid thread identifier, an agent address, and delivery of a spoofed From address to the configured IMAP inbox; FreeScout attributes and relays the reply as that agent.

CVSS severity7.5
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FreeScout before 1.8.220 allows remote attackers to impersonate agents and send forged replies to customers. FetchEmails processMessage() trusts thread and user identifiers from notification-reply Message-IDs without verifying an APP_KEY-derived HMAC. Exploitation requires a valid thread identifier, an agent address, and delivery of a spoofed From address to the configured IMAP inbox; FreeScout attributes and relays the reply as that agent.

The record

CVE
CVE-2026-47123
Published
May 29, 2026
Updated
May 29, 2026
Vendor
FreeScout
Product
FreeScout
Classifications
CWE-290, CWE-345, T1656
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 29, 2026CVE publishedPublication date reported by the CVE source.
  2. May 29, 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=< 1.8.220

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeScout · FreeScoutversion=< 1.8.220

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
CWE-345Insufficient Verification of Data Authenticity
T1656Impersonation

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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