● High · CVSS 7.2

How to Fix CVE-2026-26045: Code injection in the affected product

Q: What is the CVSS score for CVE-2026-26045?

7.2 (High). Vector: `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`.

Q: Where is the official advisory for CVE-2026-26045?

The vendor advisory is at [https://access.redhat.com/security/cve/CVE-2026-26045](https://access.redhat.com/security/cve/CVE-2026-26045). The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-26045.

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

CVE-2026-26045 is a code injection in Vendor the affected product. The fix is to apply the vendor patch noted below.

⚡ At a glance

Severity	7.2 (High)
Actively exploited?	No public listing in CISA KEV
Affected	0 to <4.5.9; 5.0.0 to <5.0.5; 5.1.0 to <5.1.2
Fixed in	See vendor advisory
Type (CWE)	CWE-94: Improper Control of Generation of Code ('Code Injection')

Exploitation status

CVE-2026-26045 has not (yet) been flagged on the CISA Known Exploited Vulnerabilities catalog; treat that as 'no confirmed exploitation on record', not 'safe to ignore'. Do not read that as all-clear: the KEV catalog often trails real-world attacks, so prioritise this on its severity rather than waiting for a listing.

Public exploit availability: no public proof-of-concept or Metasploit module is referenced in this record yet. That says nothing about private exploit code, so do not treat the issue as low risk just because none is published.

Authoritative references:

What is CVE-2026-26045?

A flaw was identified in Moodle’s backup restore functionality where specially crafted backup files were not properly validated during processing. If a malicious backup file is restored, it could lead to unintended execution of server-side code. Since restore capabilities are typically available to privileged users, exploitation requires authenticated access. Successful exploitation could result in full compromise of the Moodle server. The CVSS base score is 7.2 (High), which puts this in the upper risk band and warrants a fast patch cycle. The official advisory is at https://access.redhat.com/security/cve/CVE-2026-26045.

What you'll see

Check the version of the affected product you are running and compare it against the Affected row above (0 to <4.5.9; 5.0.0 to <5.0.5; 5.1.0 to <5.1.2). If your build sits inside the affected range, you must patch.

Run the version check that fits your platform:

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

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

How to fix CVE-2026-26045

Upgrade the affected product 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 the-affected-product
dpkg -s the-affected-product | grep -i ^Version

RHEL / CentOS / Rocky / AlmaLinux

sudo dnf upgrade --refresh the-affected-product -y
# or for older releases:
sudo yum update the-affected-product -y
rpm -q the-affected-product

SUSE / openSUSE

sudo zypper refresh
sudo zypper update the-affected-product
rpm -q the-affected-product

Complete PowerShell remediation script (Windows)

# Fix script for CVE-2026-26045 affecting the affected product
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.

$ErrorActionPreference = "Stop"
$LogPath  = "C:\Logs\CVE-2026-26045-fix-$(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"
    $pkg = Get-Package -Name "*the affected product*" -ErrorAction SilentlyContinue
    if ($pkg) { $pkg | Format-Table Name, Version }
    else { Write-Host "Not detected via Get-Package; try winget list" }

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

    Write-Host "[3/4] Apply the upgrade to See vendor advisory"
    winget upgrade --name "the affected product" --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 "the affected product"
    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-2026-26045 affecting the affected product
# Detect -> backup -> upgrade -> verify -> log.

set -euo pipefail
LOG="/var/log/cve-2026-26045-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 the-affected-product 2>/dev/null | grep -i ^Version || echo "the-affected-product not installed via dpkg"
elif command -v rpm >/dev/null; then
    rpm -q the-affected-product || echo "the-affected-product not installed via rpm"
fi

echo "[2/4] Backup configuration"
BACKUP="/root/backup-cve-2026-26045-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/the-affected-product /etc/the-affected-product.d /etc/the-affected-product.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 the-affected-product
elif command -v dnf >/dev/null; then
    dnf upgrade --refresh -y the-affected-product
elif command -v yum >/dev/null; then
    yum update -y the-affected-product
elif command -v zypper >/dev/null; then
    zypper --non-interactive update the-affected-product
fi

echo "[4/4] Verify the patched build"
if command -v dpkg >/dev/null; then
    dpkg -s the-affected-product 2>/dev/null | grep -i ^Version
elif command -v rpm >/dev/null; then
    rpm -q the-affected-product
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-2026-26045" -Direction Inbound -Action Block -Protocol TCP -LocalPort 80,443 -RemoteAddress Any -Enabled True
Get-NetFirewallRule -DisplayName "Block-CVE-2026-26045"

Disable the affected service (Linux)

sudo systemctl stop the-affected-product 2>/dev/null || true
sudo systemctl disable the-affected-product 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.

The repair

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 the-affected-product 2>/dev/null | grep -i ^Version
rpm -q the-affected-product 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 "*the affected product*" | 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.

Other defects in the same area that deserve attention during this patch cycle:

Is CVE-2026-26045 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-2026-26045?

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-2026-26045?

7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

Where is the official advisory for CVE-2026-26045?

The vendor advisory is at https://access.redhat.com/security/cve/CVE-2026-26045. The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-26045.

References

Official vendor advisory: https://access.redhat.com/security/cve/CVE-2026-26045
NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26045
CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Additional reference: https://bugzilla.redhat.com/show_bug.cgi?id=2440901

Written by Sai Kiran Pandrala on 2026-05-25. Always confirm against the vendor's advisory before applying changes in production.