● Medium · CVSS 4.4

How to Fix CVE-2026-2499: Cross-site scripting in Custom Logo

Q: What is the CVSS score for CVE-2026-2499?

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

Q: Where is the official advisory for CVE-2026-2499?

The vendor advisory is at [https://www.wordfence.com/threat-intel/vulnerabilities/id/92705581-9a0d-4d23-9118-fec9100e4ce1?source=cve](https://www.wordfence.com/threat-intel/vulnerabilities/id/92705581-9a0d-4d23-9118-fec9100e4ce1?source=cve). The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-2499.

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

CVE-2026-2499 is a cross-site scripting in tgrk Custom Logo. The fix is to apply the vendor patch noted below.

⚡ At a glance


Severity	4.4 (Medium)
Actively exploited?	No public listing in CISA KEV
Affected	Custom Logo 0 to <=2.2
Fixed in	See vendor advisory
Type (CWE)	CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

What is CVE-2026-2499?

The Custom Logo plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 2.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled. The CVSS base score is 4.4 (Medium). The official advisory is at https://www.wordfence.com/threat-intel/vulnerabilities/id/92705581-9a0d-4d23-9118-fec9100e4ce1?source=cve.

Am I affected?

Check the version of Custom Logo you are running and compare it against the Affected row above (Custom Logo 0 to <=2.2). If your build sits inside the affected range, you must patch.

Run the version check that fits your platform:


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


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

How to fix CVE-2026-2499

Upgrade Custom Logo 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 custom-logo
dpkg -s custom-logo | grep -i ^Version

RHEL / CentOS / Rocky / AlmaLinux


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

SUSE / openSUSE


sudo zypper refresh
sudo zypper update custom-logo
rpm -q custom-logo

PHP / Composer


composer update tgrk/custom-logo 2>/dev/null || composer update
composer show | head -20

WordPress


# Update via WP-CLI
wp plugin update --all
wp core update

Complete PowerShell remediation script (Windows)


# Fix script for CVE-2026-2499 affecting Custom Logo
# Run as administrator. Detect -> backup -> upgrade -> verify -> log.

$ErrorActionPreference = "Stop"
$LogPath  = "C:\Logs\CVE-2026-2499-fix-$(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"
    $pkg = Get-Package -Name "*Custom Logo*" -ErrorAction SilentlyContinue
    if ($pkg) { $pkg | Format-Table Name, Version }
    else { Write-Host "Not detected via Get-Package; try winget list" }

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

    Write-Host "[3/4] Apply the upgrade to See vendor advisory"
    winget upgrade --name "Custom Logo" --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 "Custom Logo"
    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-2026-2499 affecting Custom Logo
# Detect -> backup -> upgrade -> verify -> log.

set -euo pipefail
LOG="/var/log/cve-2026-2499-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 custom-logo 2>/dev/null | grep -i ^Version || echo "custom-logo not installed via dpkg"
elif command -v rpm >/dev/null; then
    rpm -q custom-logo || echo "custom-logo not installed via rpm"
fi

echo "[2/4] Backup configuration"
BACKUP="/root/backup-cve-2026-2499-$(date +%Y%m%d)"
mkdir -p "$BACKUP"
for d in /etc/custom-logo /etc/custom-logo.d /etc/custom-logo.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 custom-logo
elif command -v dnf >/dev/null; then
    dnf upgrade --refresh -y custom-logo
elif command -v yum >/dev/null; then
    yum update -y custom-logo
elif command -v zypper >/dev/null; then
    zypper --non-interactive update custom-logo
fi

echo "[4/4] Verify the patched build"
if command -v dpkg >/dev/null; then
    dpkg -s custom-logo 2>/dev/null | grep -i ^Version
elif command -v rpm >/dev/null; then
    rpm -q custom-logo
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-2026-2499" -Direction Inbound -Action Block -Protocol TCP -LocalPort 80,443 -RemoteAddress Any -Enabled True
Get-NetFirewallRule -DisplayName "Block-CVE-2026-2499"

Disable the affected service (Linux)


sudo systemctl stop custom-logo 2>/dev/null || true
sudo systemctl disable custom-logo 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 custom-logo 2>/dev/null | grep -i ^Version
rpm -q custom-logo 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 "*Custom Logo*" | 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-2026-26025: Null pointer dereference in smf — Null pointer dereference in smf
How to Fix CVE-2026-33241: Command Injection in salvo — Command Injection in salvo
How to Fix CVE-2026-24907: Cross-site scripting in october , Cross-site scripting in october
How to Fix CVE-2026-24679: Path Traversal in FreeRDP , Path Traversal in FreeRDP
How to Fix CVE-2026-44602: NULL Pointer Dereference in Tor , NULL Pointer Dereference in Tor

Is CVE-2026-2499 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-2026-2499?

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-2026-2499?

4.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N.

Where is the official advisory for CVE-2026-2499?

The vendor advisory is at https://www.wordfence.com/threat-intel/vulnerabilities/id/92705581-9a0d-4d23-9118-fec9100e4ce1?source=cve. The NVD record is at https://nvd.nist.gov/vuln/detail/CVE-2026-2499.

References

Official vendor advisory: https://www.wordfence.com/threat-intel/vulnerabilities/id/92705581-9a0d-4d23-9118-fec9100e4ce1?source=cve
NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2499
CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
Additional reference: https://plugins.trac.wordpress.org/browser/custom-logo/trunk/custom-logo.php#L18
Additional reference: https://plugins.trac.wordpress.org/browser/custom-logo/tags/2.2/custom-logo.php#L18

*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.*