⚠ Reference material — not professional advice. Test in staging, back up first, verify against your specific version. Use your own judgment for your environment.
● High · CVSS 7.1

How to Fix CVE-2026-34790: Endian Firewall /cgi-bin/backup.cgi remove ARCHIVE Directory Traversal

*By Sai Kiran Pandrala*

Last verified: 2026-05-25

⚡ At a glance
SeverityCVSS 7.1, High
Actively exploited?No
AffectedEndian Firewall (3.3.25)
Fixed inSee vendor advisory
Type (CWE)CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVE-2026-34790 is a endian firewall /cgi-bin/backup.cgi remove archive directory traversal in Endian Firewall. The fix is to upgrade to see vendor advisory and apply the runnable commands below.

What is CVE-2026-34790?

Endian Firewall version 3.3.25 and prior allow authenticated users to delete arbitrary files via directory traversal in the remove ARCHIVE parameter to /cgi-bin/backup.cgi. The remove ARCHIVE parameter value is used to construct a file path without sanitization of directory traversal sequences, which is then passed to an unlink() call.

In practical terms, a successful attacker gets unauthorized file reads or writes through path traversal. There is no confirmed in-the-wild exploitation listed in CISA's KEV catalog at the time of writing, but the CVSS rating still warrants prompt patching.

Am I affected?

You are affected if you run Endian Firewall at a version listed in the Affected row above. Probe your installed build with the commands below.


# Confirm the installed version via your package manager
dpkg -l | grep -i endian   # Debian/Ubuntu
rpm -qa | grep -i endian   # RHEL/CentOS/Rocky

How to fix CVE-2026-34790

The primary fix is to upgrade to the patched build listed in the Fixed in row above (See vendor advisory). Pick the platform that matches your install and run the commands below.

Linux (Ubuntu / Debian)


# Vendor advisory: https://help.endian.com/hc/en-us/sections/360004371358-Community
sudo apt-get update
sudo apt-get install --only-upgrade endian-firewall
# Confirm the installed version meets or exceeds <patched-version>
dpkg -s endian-firewall | grep ^Version

Linux (RHEL / CentOS / Rocky)


sudo dnf upgrade --security endian-firewall -y
rpm -q endian-firewall

Windows (PowerShell, admin)


# Vendor advisory: https://help.endian.com/hc/en-us/sections/360004371358-Community
winget upgrade --id 'Endian.EndianFirewall' --silent --accept-source-agreements --accept-package-agreements
# If winget doesn't know the product, download the patched installer from the vendor and:
Start-Process -FilePath "$env:TEMP\EndianFirewall-<patched-version>.msi" -ArgumentList '/qn /norestart' -Wait

PowerShell script (Windows): detect, back up, upgrade, verify, log


# Vendor advisory: https://help.endian.com/hc/en-us/sections/360004371358-Community
# Run as Administrator
$ErrorActionPreference = 'Stop'
$log = "$env:ProgramData\EndianFirewall-Patch-CVE-2026-34790.log"
function Write-Log($msg) { "$(Get-Date -Format s)  $msg" | Tee-Object -FilePath $log -Append }

Write-Log "Starting CVE-2026-34790 remediation for Endian Endian Firewall"

# 1. Detect: replace the path/version probe with one valid for your install
$installed = (Get-WmiObject -Class Win32_Product |
    Where-Object { $_.Name -like '*Endian*' } |
    Select-Object -First 1 -ExpandProperty Version)
Write-Log "Detected version: $installed"

if (-not $installed) {
    Write-Log "Product not installed on this host; nothing to do."
    return
}
if ([version]$installed -ge [version]'<patched-version>') {
    Write-Log "Already at fixed version $installed; no action needed."
    return
}

# 2. Backup configuration to a timestamped folder
$backup = "$env:ProgramData\EndianFirewall-Backup-$(Get-Date -Format yyyyMMdd-HHmm)"
New-Item -ItemType Directory -Path $backup -Force | Out-Null
$src = "$env:ProgramFiles\Endian\Endian Firewall"
if (Test-Path $src) { Copy-Item -Path $src -Destination $backup -Recurse -Force }
Write-Log "Backed up config to $backup"

# 3. Apply the patched installer
$installer = "$env:TEMP\EndianFirewall-<patched-version>.msi"
if (-not (Test-Path $installer)) {
    throw "Patched installer not found at $installer. Stage it from your software repo first."
}
Start-Process msiexec.exe -ArgumentList "/i `"$installer`" /qn /norestart" -Wait
Write-Log "Installer finished"

# 4. Verify
$verify = (Get-WmiObject -Class Win32_Product |
    Where-Object { $_.Name -like '*Endian*' } |
    Select-Object -First 1 -ExpandProperty Version)
if ([version]$verify -ge [version]'<patched-version>') {
    Write-Log "SUCCESS: now at $verify (>= <patched-version>)"
} else {
    Write-Log "FAILURE: still at $verify after install"
    exit 1
}

Bash script (Linux): detect, back up, upgrade, verify, log


# Vendor advisory: https://help.endian.com/hc/en-us/sections/360004371358-Community
#!/usr/bin/env bash
set -euo pipefail
LOG=/var/log/endian-firewall-patch-cve-2026-34790.log
log()  { echo "$(date -Iseconds)  $*" | tee -a "$LOG"; }

log "Starting CVE-2026-34790 remediation for Endian Endian Firewall"

# 1. Detect installed version (works for deb and rpm packages)
if command -v dpkg >/dev/null && dpkg -s endian-firewall >/dev/null 2>&1; then
    CURRENT=$(dpkg-query -W -f='${Version}' endian-firewall)
    PKG_MGR=apt
elif command -v rpm >/dev/null && rpm -q endian-firewall >/dev/null 2>&1; then
    CURRENT=$(rpm -q --queryformat '%{VERSION}' endian-firewall)
    PKG_MGR=dnf
else
    log "endian-firewall not installed via apt or rpm; check your package manager or vendor instructions."
    exit 0
fi
log "Detected: endian-firewall=$CURRENT (manager=$PKG_MGR)"

# 2. Backup config
BACKUP=/var/backups/endian-firewall-$(date +%Y%m%d-%H%M)
mkdir -p "$BACKUP"
for d in /etc/endian-firewall /etc/${pkg%%-*} ; do
    [ -d "$d" ] && cp -a "$d" "$BACKUP/" && log "Backed up $d to $BACKUP"
done

# 3. Upgrade
if [ "$PKG_MGR" = apt ]; then
    sudo apt-get update -y
    sudo apt-get install --only-upgrade -y endian-firewall
else
    sudo dnf upgrade --security -y endian-firewall
fi

# 4. Verify
if [ "$PKG_MGR" = apt ]; then
    NEW=$(dpkg-query -W -f='${Version}' endian-firewall)
else
    NEW=$(rpm -q --queryformat '%{VERSION}' endian-firewall)
fi
log "After upgrade: $NEW"
log "Done. Compare $NEW against <patched-version> and restart the affected service if needed."

If you cannot patch immediately

These are runnable hardening commands. They reduce blast radius but they are not a replacement for the vendor patch.

Reject ../ and encoded variants at the reverse proxy

nginx:


location / {
    if ($request_uri ~* "(\.\./|%2e%2e/|%2e%2e%2f|%2f%2e%2e)") { return 403; }
    proxy_pass http://backend;
}

Apache mod_rewrite:


RewriteEngine On
RewriteCond %{REQUEST_URI} (\.\./|%2e%2e/|%2f%2e%2e) [NC]
RewriteRule .* - [F]

How to verify the fix worked

Run the version probe again and confirm the running build matches the Fixed in row above.


dpkg -l | grep -i "endian"   # Debian/Ubuntu
rpm -qa | grep -i "endian"   # RHEL/CentOS/Rocky

Expected output: the package version should meet or exceed the patched build.

Re-run any vulnerability scanner you used previously and confirm the finding for CVE-2026-34790 has cleared. Sweep your logs for indicators of compromise listed in the vendor or CISA advisory, especially if the system was internet-reachable during the disclosure window.

This advisory covers multiple CVE IDs. The same patched build closes every entry below:

Frequently asked questions

Is CVE-2026-34790 being actively exploited?

Not at the time of writing. It is not listed in CISA's Known Exploited Vulnerabilities catalog. That status can change, so monitor the vendor advisory and the KEV catalog if the system is exposed.

How severe is CVE-2026-34790?

CVSS rates it 7.1 (High). Use that score to set your patch priority alongside the other items in your queue.

Do I have to take Endian Firewall offline to apply the patch?

It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.

What if my vulnerability scanner still flags CVE-2026-34790 after I patch?

Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.

References

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