CVE-2026-28289Public exploitNetwork attack vector

Unauthenticated code execution via filename sanitization bypass

Published Mar 3, 2026 · Updated Mar 3, 2026

Unrestricted file upload in FreeScout before 1.8.207 allows remote attackers to execute code by emailing crafted attachments. sanitizeUploadedFileName() in app/Misc/Helper.php checks for a leading dot before stripping Unicode format characters, so a zero-width-space prefix becomes a valid .htaccess filename on disk. The unauthenticated path requires a configured mailbox to ingest the email automatically and a web-server configuration that honors the uploaded .htaccess file.

CVSS severity10.0
Critical
EPSS probability31.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in FreeScout before 1.8.207 allows remote attackers to execute code by emailing crafted attachments. sanitizeUploadedFileName() in app/Misc/Helper.php checks for a leading dot before stripping Unicode format characters, so a zero-width-space prefix becomes a valid .htaccess filename on disk. The unauthenticated path requires a configured mailbox to ingest the email automatically and a web-server configuration that honors the uploaded .htaccess file.

The record

CVE
CVE-2026-28289
Published
Mar 3, 2026
Updated
Mar 3, 2026
Vendor
FreeScout
Product
FreeScout
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 3, 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=< 1.8.207

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeScout · FreeScoutversion=< 1.8.207

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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.

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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-434Unrestricted Upload of File with Dangerous Type
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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