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NVD / CVE Program· CNA GitHub_M

CVE-2026-47123: FreeScout: Agent Impersonation via Missing HMAC Verification on Notification Reply Message-ID Path

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.14% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: freescout-help-desk freescout 1.8.220.

Low priority for now. Upgrade to freescout-help-desk freescout 1.8.220 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to 1.8.220, the email processing pipeline in FreeScout's FetchEmails command has two code paths for identifying agent (user) replies based on In-Reply-To / References headers. The notification reply path (notify-{thread_id}-{user_id}-...) extracts thread_id and user_id directly from the Message-ID without HMAC verification. An external attacker who can spoof the From address of a helpdesk agent can inject messages that FreeScout processes as legitimate agent replies — which are then automatically forwarded to customers via the legitimate SMTP server. This vulnerability is fixed in 1.8.220.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
May 29, 2026
Updated
Jul 22, 2026
EPSS
0.1% · 3th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-47123

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • freescout-help-desk freescout

    • < 1.8.220affected

Same product

freescout-help-desk: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-53595FreeScout vulnerable to anonymous account takeover via /user-setup empty invite_hash on MySQL
    38Monitor
  • CVE-2026-41902FreeScout's user invitation hash never expires: permanent unauthenticated account takeover if invite link leaks
    36Monitor
  • CVE-2026-41193FreeScout has Zip Slip path traversal in module installation that allows arbitrary file write leading to RCE
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-41906May 7, 2026 · FreeScout: Conversation Change-Customer Cross-Mailbox Authorization Bypass
    28Monitor
  • ← EarlierCVE-2026-45294May 29, 2026 · FreeScout: User Account Enumeration via Password Reset Response Differentiation
    21Monitor
  • Later →CVE-2026-48810May 29, 2026 · FreeScout: Thread Edit Authorization Bypass via Missing Mailbox Check
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
freescout-help-desk freescout1.8.220 · descriptionVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-4119338 days apartFreeScout has Zip Slip path traversal in module installation that allows arbitrary file write leading to RCE
    36Monitor
  • CVE-2026-5359352 days apartFreeScout Vulnerable to Authenticated Remote Code Execution via incomplete upload extension denylist (.pht) — bypass of CVE-2025-48471
    35Monitor
  • CVE-2026-4190522 days apartFreeScout vulnerable to SSRF via Helper::sanitizeRemoteUrl: redirect destination not re-validated, allowing internal HTTP / cloud-metadata access
    30Monitor
  • CVE-2026-4056638 days apartFreeScout vulnerable to SSRF via IMAP/SMTP Connection Test Endpoints
    16Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
low · data can be read
Integrity
high · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality impact
Low
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-290 · Authentication Bypass by Spoofing

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records