● High · CVSS 8.5

How to Fix CVE-2026-2637: Incorrect permission assignment in iBoysoft NTFS

Q: What is the CVSS score for CVE-2026-2637?

8.5 (High). Vector: `CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`.

Q: Where is the official advisory for CVE-2026-2637?

The vendor advisory is at [https://fluidattacks.com/advisories/cuarteto](https://fluidattacks.com/advisories/cuarteto). The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-2637.

By Sai Kiran Pandrala. Last verified: 2026-05-25.

CVE-2026-2637 is a incorrect permission assignment in iBoysoft iBoysoft NTFS. The fix is to apply the vendor patch noted below.

⚡ At a glance


Severity	8.5 (High)
Actively exploited?	No public listing in CISA KEV
Affected	iBoysoft NTFS 8.0.0
Fixed in	See vendor advisory
Type (CWE)	CWE-732 Incorrect Permission Assignment for Critical Resource

What is CVE-2026-2637?

iBoysoft NTFS for Mac contains a local privilege escalation vulnerability in its privileged helper daemon ntfshelperd. The daemon exposes an NSConnection service that runs as root without implementing any authentication or authorization checks.

This issue affects iBoysoft NTFS: 8.0.0. The CVSS base score is 8.5 (High), which puts this in the upper risk band and warrants a fast patch cycle. The official advisory is at https://fluidattacks.com/advisories/cuarteto.

Am I affected?

Check the version of iBoysoft NTFS you are running and compare it against the Affected row above (iBoysoft NTFS 8.0.0). If your build sits inside the affected range, you must patch.

Run the version check that fits your platform:


# Linux package check
dpkg -s iboysoft-ntfs 2>/dev/null | grep -i ^Version
rpm -q iboysoft-ntfs 2>/dev/null
command -v iboysoft-ntfs >/dev/null && iboysoft-ntfs --version 2>/dev/null


# Windows (PowerShell)
Get-Package -Name "*iBoysoft NTFS*" -ErrorAction SilentlyContinue | Select-Object Name, Version
winget list --name "iBoysoft NTFS" 2>$null

How to fix CVE-2026-2637

Upgrade iBoysoft NTFS to a patched build: See vendor advisory. The vendor advisory is the source of truth for the exact fixed version.

Ubuntu / Debian


sudo apt-get update
sudo apt-get install --only-upgrade iboysoft-ntfs
dpkg -s iboysoft-ntfs | grep -i ^Version

RHEL / CentOS / Rocky / AlmaLinux


sudo dnf upgrade --refresh iboysoft-ntfs -y
# or for older releases:
sudo yum update iboysoft-ntfs -y
rpm -q iboysoft-ntfs

SUSE / openSUSE


sudo zypper refresh
sudo zypper update iboysoft-ntfs
rpm -q iboysoft-ntfs

Complete PowerShell remediation script (Windows)


# Fix script for CVE-2026-2637 affecting iBoysoft NTFS
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.

$ErrorActionPreference = "Stop"
$LogPath  = "C:\Logs\CVE-2026-2637-fix-$(Get-Date -Format yyyyMMdd-HHmmss).log"
New-Item -ItemType Directory -Force (Split-Path $LogPath) | Out-Null
Start-Transcript -Path $LogPath -Append

try {
    Write-Host "[1/4] Detect installed version"
    $pkg = Get-Package -Name "*iBoysoft NTFS*" -ErrorAction SilentlyContinue
    if ($pkg) { $pkg | Format-Table Name, Version }
    else { Write-Host "Not detected via Get-Package; try winget list" }

    Write-Host "[2/4] Backup configuration"
    $backup = "C:\Backup\iboysoft-ntfs-$(Get-Date -Format yyyyMMdd)"
    New-Item -ItemType Directory -Force $backup | Out-Null
    Get-ChildItem "C:\ProgramData\iBoysoft NTFS" -ErrorAction SilentlyContinue |
        Copy-Item -Destination $backup -Recurse -Force -ErrorAction SilentlyContinue

    Write-Host "[3/4] Apply the upgrade to See vendor advisory"
    winget upgrade --name "iBoysoft NTFS" --silent --accept-source-agreements --accept-package-agreements
    if ($LASTEXITCODE -ne 0) {
        # Fallback: pull latest via OS update channel
        Install-Module -Name PSWindowsUpdate -Force -SkipPublisherCheck -ErrorAction SilentlyContinue
        Import-Module PSWindowsUpdate
        Install-WindowsUpdate -MicrosoftUpdate -AcceptAll -IgnoreReboot
    }

    Write-Host "[4/4] Verify the patched build"
    winget list --name "iBoysoft NTFS"
    Write-Host "Patch applied. Reboot if prompted."
    exit 0
} catch {
    Write-Error "Patch failed: $_"
    exit 1
} finally {
    Stop-Transcript
}

Complete Bash remediation script (Linux)


#!/usr/bin/env bash
# Fix script for CVE-2026-2637 affecting iBoysoft NTFS
# Detect -> backup -> upgrade -> verify -> log.

set -euo pipefail
LOG="/var/log/cve-2026-2637-fix-$(date +%Y%m%d-%H%M%S).log"
exec > >(tee -a "$LOG") 2>&1

echo "[1/4] Detect installed version"
if command -v dpkg >/dev/null; then
    dpkg -s iboysoft-ntfs 2>/dev/null | grep -i ^Version || echo "iboysoft-ntfs not installed via dpkg"
elif command -v rpm >/dev/null; then
    rpm -q iboysoft-ntfs || echo "iboysoft-ntfs not installed via rpm"
fi

echo "[2/4] Backup configuration"
BACKUP="/root/backup-cve-2026-2637-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/iboysoft-ntfs /etc/iboysoft-ntfs.d /etc/iboysoft-ntfs.conf; do
    [ -e "$d" ] && cp -a "$d" "$BACKUP/" || true
done

echo "[3/4] Apply the upgrade (target: See vendor advisory)"
if command -v apt-get >/dev/null; then
    apt-get update
    apt-get install --only-upgrade -y iboysoft-ntfs
elif command -v dnf >/dev/null; then
    dnf upgrade --refresh -y iboysoft-ntfs
elif command -v yum >/dev/null; then
    yum update -y iboysoft-ntfs
elif command -v zypper >/dev/null; then
    zypper --non-interactive update iboysoft-ntfs
fi

echo "[4/4] Verify the patched build"
if command -v dpkg >/dev/null; then
    dpkg -s iboysoft-ntfs 2>/dev/null | grep -i ^Version
elif command -v rpm >/dev/null; then
    rpm -q iboysoft-ntfs
fi
echo "Done. Restart any service that loaded the old library."

If you can't patch immediately

Apply at least one of the following inline controls until you can deploy the patched build. None replace the upgrade.

Restrict exposure with nftables (Linux)


# Allow only trusted CIDR to reach the affected service ports
sudo nft add table inet filter 2>/dev/null || true
sudo nft 'add chain inet filter input { type filter hook input priority 0 ; }' 2>/dev/null || true
sudo nft 'add rule inet filter input tcp dport {80, 443} ip saddr != 10.0.0.0/8 drop'
sudo nft list ruleset

Block at the host firewall (Windows)


New-NetFirewallRule -DisplayName "Block-CVE-2026-2637" -Direction Inbound -Action Block -Protocol TCP -LocalPort 80,443 -RemoteAddress Any -Enabled True
Get-NetFirewallRule -DisplayName "Block-CVE-2026-2637"

Disable the affected service (Linux)


sudo systemctl stop iboysoft-ntfs 2>/dev/null || true
sudo systemctl disable iboysoft-ntfs 2>/dev/null || true

If the vendor advisory lists an official workaround, prefer that wording verbatim. If no workaround is published, the only safe remediation is the patch.

How to verify the fix worked

After upgrading, confirm the installed version matches the patched build and that no old library is still loaded by a long-running process.


# Linux
dpkg -s iboysoft-ntfs 2>/dev/null | grep -i ^Version
rpm -q iboysoft-ntfs 2>/dev/null || true
# Pid map check for old library handles
sudo lsof +c0 2>/dev/null | grep -i "DEL.*lib" || true


# Windows
Get-Package -Name "*iBoysoft NTFS*" | Select-Object Name, Version
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5

Expected: the reported version is at or above See vendor advisory. Restart the affected service (systemctl restart <service> on Linux, or restart the Windows service) so it loads the patched binary.

Frequently asked questions

Other vulnerabilities in the same area that are worth patching alongside this one:

How to Fix CVE-2026-20972: Critical Vulnerability in Samsung Mobile Devices — Critical Vulnerability in Samsung Mobile Devices
How to Fix CVE-2026-34244: Information disclosure in weblate — Information disclosure in weblate
How to Fix CVE-2026-37982: Critical Vulnerability in Red Hat build of Keycloak 26.4 , Critical Vulnerability in Red Hat build of Keycloak 26.4
How to Fix CVE-2026-34155: RAUC: Improper Signing of Plain Bundles Exceeding 2 GiB in rauc , RAUC: Improper Signing of Plain Bundles Exceeding 2 GiB in rauc
How to Fix CVE-2026-23885: Code Injection RCE in alchemy_cms , Code Injection RCE in alchemy_cms

Is CVE-2026-2637 actively exploited?

There is no public confirmation of exploitation in the wild listed in CISA KEV at the time of this writing. Patch anyway. Public exploits commonly follow disclosure within weeks.

Do I need to reboot after patching CVE-2026-2637?

For kernel and OS-level updates, yes. For most userland packages a systemctl restart <service> is enough on Linux, and restarting the Windows service or app on Windows. Any process that loaded the old library keeps using it until restarted.

What is the CVSS score for CVE-2026-2637?

8.5 (High). Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N.

Where is the official advisory for CVE-2026-2637?

The vendor advisory is at https://fluidattacks.com/advisories/cuarteto. The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-2637.

References

Official vendor advisory: https://fluidattacks.com/advisories/cuarteto
NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2637
CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Additional reference: https://iboysoft.com/ntfs-for-mac/

*Written by Sai Kiran Pandrala. Assembled from the official vendor advisory, NVD record, and CISA KEV listing on 2026-05-25. Always confirm against the vendor's advisory before applying changes in production.*