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NVD / CVE Program· CNA GitHub_M

CVE-2026-28289: FreeScout 1.8.206 Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Remote Code Execution

Noroxi assessment

Priority: This week (action score 60/100)

  • A ready-made attack module is public (Metasploit); exploiting it takes no special expertise.
  • A ready-made attack tool exists and the flaw can be exploited over the network without an account, so priority is at least “This week”.
  • Probability of exploitation in the next 30 days: 35.1% (FIRST EPSS); higher than 98.4% of all records.
  • 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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: freescout-help-desk freescout 1.8.207.

Don’t wait for the next maintenance window. Upgrade to freescout-help-desk freescout 1.8.207 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. A patch bypass vulnerability for CVE-2026-27636 in FreeScout 1.8.206 and earlier allows any authenticated user with file upload permissions to achieve Remote Code Execution (RCE) on the server by uploading a malicious .htaccess file using a zero-width space character prefix to bypass the security check. The vulnerability exists in the sanitizeUploadedFileName() function in app/Http/Helper.php. The function contains a Time-of-Check to Time-of-Use (TOCTOU) flaw where the dot-prefix check occurs before sanitization removes invisible characters. This vulnerability is fixed in 1.8.207.

HighCVSS 8.1 · v3.1—Weaponized Fix available
Published
Mar 3, 2026
Updated
Jun 17, 2026
EPSS
35.1% · 98th percentile

Report tools

JSON

Action score

60

This week

Don’t wait for the next maintenance window.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
11 / 30 · 35.1%
Ready-made attack tool
17 / 60 · floor: at least 60

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
8.1
CNA · GitHub_M
10.0
1.9 point gap

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

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
  • Weaponized exploit exists
  • A fix has been released

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

Follow CVE-2026-28289

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.

VendorProduct
freescoutfreescout

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • freescout freescoutbefore 1.8.207

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

    • < 1.8.207affected

Same product

freescout: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-27636FreeScout: Missing .htaccess in Restricted File Extensions Allows Remote Code Execution on Apache
    40Plan
  • CVE-2026-27637FreeScout's Predictable Authentication Token Enables Account Takeover
    39Monitor
  • CVE-2026-32754FreeScout: Stored XSS via Unescaped Email Template Rendering ({!! $thread->body !!})
    37Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-54366Jul 26, 2025 · FreeScout's deserialization of untrusted data leads to Remote Code Execution
    34Monitor
  • ← EarlierCVE-2025-58163Sep 3, 2025 · FreeScout's deserialization of untrusted data can lead to Remote Code Execution
    34Monitor
  • Later →CVE-2026-32752Mar 19, 2026 · FreeScout: Broken Access Control in ThreadPolicy — Any User Can Read/Edit All Customer Messages
    32Monitor

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 freescout1.8.207 · descriptionVendor (CNA)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Metasploit moduleexploit/multi/http/freescout_htaccess_rceFreeScout Unauthenticated RCE via ZWSP .htaccess Bypassexploit2026-03-01
Proof-of-concept repository on GitHubstars:12026-03-05

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.

  1. Metasploit-3 d
  2. Published
  3. First PoC+1 d
  4. TodayNov 4, 2026+246 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

  • CVE-2026-276366 days apartFreeScout: Missing .htaccess in Restricted File Extensions Allows Remote Code Execution on Apache
    40Plan
  • CVE-2025-48471278 days apartFreeScout Vulnerable to Arbitrary File Upload
    28Monitor

Chain candidates

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

—

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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-434 · Unrestricted Upload of File with Dangerous Type

CVSS vector

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

nvd-primary

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

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

All records