CVE-2026-119977: WordPress Core TOCTOU Race Condition Added to CISA KEV — Detection and Remediation Guide

---
title: WordPress TOCTOU Race Condition File Upload Exploitation
id: 8f3a9c41-7d2b-4e5f-9a1c-3d8e6f2b4a7c
status: experimental
description: Detects rapid file creation and modification patterns indicative of TOCTOU race condition exploitation in WordPress uploads directory
references:
  - https://www.cisa.gov/known-exploited-vulnerabilities-catalog
  - https://attack.mitre.org/techniques/T1106/
author: Security Arsenal
date: 2026/11/03
tags:
  - attack.execution
  - attack.t1106
  - attack.t1190
logsource:
  category: file_event
  product: linux
detection:
  selection_path:
    TargetFilename|contains: '/wp-content/uploads/'
  selection_php:
    TargetFilename|endswith: '.php'
  selection_webserver:
    Image|contains:
      - '/apache'
      - '/nginx'
      - '/php-fpm'
  condition: selection_path and selection_php and selection_webserver
falsepositives:
  - Legitimate plugin installations that create PHP files in uploads directory (rare and should be investigated)
  - Custom WordPress themes with upload handlers
level: high
---
title: Suspicious WordPress File Upload Pattern - Rapid Succession
id: 3c7f2a89-5b4d-4e8a-9c1f-2d6e8a3b5f9d
status: experimental
description: Detects multiple file uploads to WordPress within a very short timeframe, characteristic of race condition exploitation attempts
references:
  - https://www.cisa.gov/news-events/alerts/2026/11/03/cisa-adds-one-known-exploited-vulnerability-catalog
author: Security Arsenal
date: 2026/11/03
tags:
  - attack.initial_access
  - attack.t1190
logsource:
  category: webserver
  product: linux
detection:
  selection:
    cs-method: 'POST'
    cs-uri-stem|contains:
      - '/wp-admin/async-upload.php'
      - '/wp-admin/media-new.php'
      - '/wp-json/wp/v2/media'
  timeframe: 2s
  condition: selection | count() > 3
falsepositives:
  - Bulk media uploads by administrators
  - Automated content migration scripts
  - CDN synchronization processes
level: medium
---
title: Web Shell Creation Following WordPress Upload
id: 6a1f8c24-9e3b-4d7a-8c2f-4b5e9a6d3f8c
status: experimental
description: Detects execution of PHP files from WordPress uploads directory, indicative of successful web shell deployment via TOCTOU exploitation
references:
  - https://attack.mitre.org/techniques/T1505/003/
author: Security Arsenal
date: 2026/11/03
tags:
  - attack.persistence
  - attack.t1505.003
  - attack.execution
logsource:
  category: webserver
  product: linux
detection:
  selection:
    cs-uri-stem|contains: '/wp-content/uploads/'
    cs-uri-stem|endswith: '.php'
    sc-status: 200
  filter_known_plugins:
    cs-uri-stem|contains:
      - '/wp-content/uploads/woocommerce_uploads/'
      - '/wp-content/uploads/gravity_forms/'
  condition: selection and not filter_known_plugins
falsepositives:
  - Certain backup plugins that generate PHP files in uploads (investigate and whitelist)
  - Custom upload handlers (should be moved out of uploads directory)
level: critical

// Hunt for WordPress TOCTOU race condition exploitation attempts
// Detects rapid file upload patterns and suspicious PHP file creation in uploads directory

// Query 1: Identify multiple rapid upload attempts to WordPress endpoints
let TimeThreshold = 2s;
let UploadThreshold = 3;
CommonSecurityLog
| where TimeGenerated > ago(24h)
| where RequestMethod == "POST"
| where RequestURL has_any ("wp-admin/async-upload.php", "wp-admin/media-new.php", "wp-json/wp/v2/media")
| summarize UploadCount = count(), 
            UniqueFiles = dcount(RequestURL),
            FileTypes = make_set(RequestURL)
    by SourceIP, DestinationHostName, bin(TimeGenerated, TimeThreshold)
| where UploadCount > UploadThreshold
| project TimeGenerated, SourceIP, DestinationHostName, UploadCount, UniqueFiles, FileTypes
| order by UploadCount desc;

// Query 2: Detect PHP file execution from uploads directory (web shell indicator)
CommonSecurityLog
| where TimeGenerated > ago(24h)
| where RequestURL has "/wp-content/uploads/" and RequestURL endswith ".php"
| where not(RequestURL has_any ("woocommerce_uploads", "gravity_forms")) // Whitelist known plugins
| extend FileName = extract(@"([^/]+\.php)", 1, RequestURL)
| summarize FirstSeen = min(TimeGenerated), 
            LastSeen = max(TimeGenerated),
            RequestCount = count(),
            SourceIPs = make_set(SourceIP)
    by DestinationHostName, FileName, RequestURL
| extend SuspicionScore = case(
    RequestCount < 5 and array_length(SourceIPs) == 1, "High - Newly created file with limited access",
    RequestCount > 100, "High - Heavy automated access",
    "Medium"
)
| order by FirstSeen desc;

// Query 3: Correlate upload attempts with subsequent suspicious activity
let SuspiciousUploads = CommonSecurityLog
| where TimeGenerated > ago(24h)
| where RequestMethod == "POST"
| where RequestURL has "wp-admin/async-upload.php"
| summarize UploadCount = count() by SourceIP, DestinationHostName, bin(TimeGenerated, 1m)
| where UploadCount >= 3
| project SourceIP, DestinationHostName, UploadWindow = TimeGenerated;
SuspiciousUploads
| join kind=inner (
    CommonSecurityLog
    | where TimeGenerated > ago(24h)
    | where RequestURL has "/wp-content/uploads/" and RequestURL endswith ".php"
) on SourceIP, DestinationHostName
| where TimeGenerated between (UploadWindow .. UploadWindow + 5m)
| project UploadWindow, SourceIP, DestinationHostName, UploadCount, 
          SuspiciousFileAccess = RequestURL, AccessTime = TimeGenerated
| order by UploadWindow desc;

-- Hunt for WordPress TOCTOU exploitation artifacts
-- Detects suspicious PHP files in uploads directory and web shell indicators

-- Artifact 1: Identify recently created PHP files in WordPress uploads directory
LET uploads_php = SELECT 
    FullPath,
    Mtime,
    Ctime,
    Size,
    Mode,
    Uid,
    Gid
FROM glob(globs='/var/www/*/wp-content/uploads/**/*.php')
WHERE Mtime > (now() - 86400 * 7)  -- Files modified in last 7 days
ORDER BY Mtime DESC

SELECT 
    FullPath,
    Mtime as ModifiedTime,
    Ctime as CreatedTime,
    Size,
    Mode as Permissions,
    Uid as UserID,
    Gid as GroupID,
    read_file(filename=FullPath, length=200) as FileHeader
FROM uploads_php
WHERE Size < 10000  -- Web shells typically small
   OR FileHeader =~ 'eval|base64_decode|gzinflate|shell_exec|system|passthru'

-- Artifact 2: Detect symbolic link manipulation in uploads directory (TOCTOU indicator)
LET symlinks = SELECT 
    FullPath,
    Mtime,
    readlink(filename=FullPath) as LinkTarget
FROM glob(globs='/var/www/*/wp-content/uploads/**/*')
WHERE Mode =~ 'l'  -- Symbolic links
   AND Mtime > (now() - 86400 * 3)  -- Recent links

SELECT 
    FullPath,
    LinkTarget,
    Mtime as CreatedTime,
    CASE 
        WHEN LinkTarget =~ 'wp-config|wp-includes|wp-admin' THEN 'CRITICAL - Links to WordPress core'
        WHEN LinkTarget =~ '^/etc|^/var|^/root' THEN 'CRITICAL - Links to system files'
        ELSE 'Suspicious'
    END as ThreatLevel
FROM symlinks
WHERE LinkTarget IS NOT NULL

-- Artifact 3: Network connections from PHP processes (post-exploitation indicator)
SELECT 
    Pid,
    Name,
    Exe,
    CommandLine,
    Username,
    netstat().RemoteAddr as RemoteAddress,
    netstat().RemotePort as RemotePort,
    netstat().State as ConnectionState
FROM pslist()
WHERE Name =~ 'php-fpm|php-cgi|php '
   AND CommandLine =~ 'wp-content/uploads'
   AND netstat().State =~ 'ESTABLISHED'
ORDER BY Pid

#!/bin/bash
# WordPress CVE-2026-119977 TOCTOU Race Condition Remediation Script
# Run with: sudo bash wordpress_toctou_remediation.sh

set -euo pipefail

# Color codes for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

echo -e "${GREEN}[+] WordPress CVE-2026-119977 Remediation Script${NC}"
echo -e "${GREEN}[+] Starting security check and remediation...${NC}\n"

# Function to check if running as root
check_root() {
    if [[ $EUID -ne 0 ]]; then
        echo -e "${RED}[!] This script must be run as root (use sudo)${NC}"
        exit 1
    fi
}

# Function to backup WordPress installation
backup_wordpress() {
    local WP_PATH="$1"
    local BACKUP_DIR="/var/backups/wordpress_pre_cve_2026_119977_$(date +%Y%m%d_%H%M%S)"
    
    echo -e "${YELLOW}[*] Creating backup of $WP_PATH to $BACKUP_DIR${NC}"
    mkdir -p "$BACKUP_DIR"
    cp -r "$WP_PATH" "$BACKUP_DIR/"
    
    # Backup database if wp-config.php exists
    if [[ -f "$WP_PATH/wp-config.php" ]]; then
        DB_NAME=$(grep DB_NAME "$WP_PATH/wp-config.php" | cut -d "'" -f 4)
        DB_USER=$(grep DB_USER "$WP_PATH/wp-config.php" | cut -d "'" -f 4)
        DB_PASS=$(grep DB_PASSWORD "$WP_PATH/wp-config.php" | cut -d "'" -f 4)
        
        echo -e "${YELLOW}[*] Backing up database: $DB_NAME${NC}"
        mysqldump -u"$DB_USER" -p"$DB_PASS" "$DB_NAME" > "$BACKUP_DIR/database_backup.sql"
    fi
    
    echo -e "${GREEN}[+] Backup completed: $BACKUP_DIR${NC}"
}

# Function to check WordPress version
check_wp_version() {
    local WP_PATH="$1"
    local VERSION_FILE="$WP_PATH/wp-includes/version.php"
    
    if [[ ! -f "$VERSION_FILE" ]]; then
        echo -e "${RED}[!] WordPress version file not found: $VERSION_FILE${NC}"
        return 1
    fi
    
    local WP_VERSION=$(grep "\$wp_version" "$VERSION_FILE" | cut -d "'" -f 2)
    echo -e "${YELLOW}[*] Current WordPress version: $WP_VERSION${NC}"
    
    # Check if version is vulnerable (< 6.8.2)
    if [[ $(echo "$WP_VERSION 6.8.2" | tr " " "\n" | sort -V | head -n 1) != "6.8.2" ]]; then
        echo -e "${RED}[!] VULNERABLE VERSION DETECTED: $WP_VERSION${NC}"
        return 0
    else
        echo -e "${GREEN}[+] WordPress version is patched: $WP_VERSION${NC}"
        return 1
    fi
}

# Function to update WordPress
update_wordpress() {
    local WP_PATH="$1"
    
    echo -e "${YELLOW}[*] Updating WordPress to latest version...${NC}"
    
    # Check if WP-CLI is available
    if command -v wp &> /dev/null; then
        cd "$WP_PATH"
        sudo -u www-data wp core update --allow-root
        sudo -u www-data wp core update-db --allow-root
        echo -e "${GREEN}[+] WordPress updated successfully using WP-CLI${NC}"
    else
        echo -e "${YELLOW}[*] WP-CLI not found. Please update manually:${NC}"
        echo -e "${YELLOW}    1. Download WordPress 6.8.2+ from https://wordpress.org/download/${NC}"
        echo -e "${YELLOW}    2. Replace wp-admin and wp-includes directories${NC}"
        echo -e "${YELLOW}    3. Update root WordPress files (wp-*.php)${NC}"
        return 1
    fi
}

# Function to detect web shells in uploads directory
detect_webshells() {
    local WP_PATH="$1"
    local UPLOADS_DIR="$WP_PATH/wp-content/uploads"
    
    echo -e "${YELLOW}[*] Scanning for web shells in uploads directory...${NC}"
    
    if [[ ! -d "$UPLOADS_DIR" ]]; then
        echo -e "${RED}[!] Uploads directory not found: $UPLOADS_DIR${NC}"
        return 1
    fi
    
    # Find PHP files in uploads directory
    local PHP_FILES=$(find "$UPLOADS_DIR" -name "*.php" -type f 2>/dev/null || true)
    
    if [[ -z "$PHP_FILES" ]]; then
        echo -e "${GREEN}[+] No PHP files found in uploads directory (expected)${NC}"
    else
        echo -e "${RED}[!] PHP FILES DETECTED IN UPLOADS DIRECTORY:${NC}"
        echo "$PHP_FILES"
        
        # Check for common web shell signatures
        while IFS= read -r file; do
            if grep -qE "eval\(|base64_decode\(|gzinflate\(|shell_exec\(|system\(|passthru\(" "$file" 2>/dev/null; then
                echo -e "${RED}[!] SUSPICIOUS FILE: $file${NC}"
                echo -e "${YELLOW}[*] First 5 lines:${NC}"
                head -n 5 "$file"
                echo ""
            fi
        done <<< "$PHP_FILES"
    fi
    
    # Check for symbolic links
    echo -e "${YELLOW}[*] Checking for suspicious symbolic links...${NC}"
    local SYMLINKS=$(find "$UPLOADS_DIR" -type l 2>/dev/null || true)
    
    if [[ -n "$SYMLINKS" ]]; then
        echo -e "${RED}[!] SYMBOLIC LINKS DETECTED:${NC}"
        while IFS= read -r link; do
            echo -e "${RED}    $link -> $(readlink "$link")${NC}"
        done <<< "$SYMLINKS"
    else
        echo -e "${GREEN}[+] No symbolic links found${NC}"
    fi
}

# Function to harden WordPress uploads directory
harden_uploads() {
    local WP_PATH="$1"
    local UPLOADS_DIR="$WP_PATH/wp-content/uploads"
    
    echo -e "${YELLOW}[*] Hardening uploads directory...${NC}"
    
    # Create .htaccess to prevent PHP execution in uploads
    cat > "$UPLOADS_DIR/.htaccess" << 'EOF'
# Disable PHP execution in uploads directory
<Files *.php>
    Order Deny,Allow
    Deny from all
</Files>

# Prevent directory browsing
Options -Indexes

# Protect against script execution
RemoveHandler .php .phtml .php3 .php4 .php5
RemoveType .php .phtml .php3 .php4 .php5
EOF
    
    chown www-data:www-data "$UPLOADS_DIR/.htaccess"
    chmod 644 "$UPLOADS_DIR/.htaccess"
    
    echo -e "${GREEN}[+] Created .htaccess to disable PHP execution in uploads${NC}"
    
    # Set proper permissions
    echo -e "${YELLOW}[*] Setting secure permissions on uploads directory...${NC}"
    find "$UPLOADS_DIR" -type d -exec chmod 755 {} \;
    find "$UPLOADS_DIR" -type f -exec chmod 644 {} \;
    
    echo -e "${GREEN}[+] Permissions hardened${NC}"
}

# Function to check for compromised WordPress core files
check_core_integrity() {
    local WP_PATH="$1"
    
    echo -e "${YELLOW}[*] Checking WordPress core file integrity...${NC}"
    
    if command -v wp &> /dev/null; then
        cd "$WP_PATH"
        if sudo -u www-data wp core verify-checksums --allow-root; then
            echo -e "${GREEN}[+] WordPress core files are intact${NC}"
        else
            echo -e "${RED}[!] WORDPRESS CORE FILES HAVE BEEN MODIFIED!${NC}"
            echo -e "${RED}[!] This may indicate compromise. Full forensic investigation recommended.${NC}"
        fi
    else
        echo -e "${YELLOW}[*] WP-CLI not available. Manual integrity check required.${NC}"
    fi
}

# Main execution
main() {
    check_root
    
    # Find WordPress installations
    echo -e "${YELLOW}[*] Searching for WordPress installations...${NC}"
    WP_INSTALLS=$(find /var/www /home -name "wp-config.php" -type f 2>/dev/null | xargs dirname || true)
    
    if [[ -z "$WP_INSTALLS" ]]; then
        echo -e "${RED}[!] No WordPress installations found${NC}"
        exit 1
    fi
    
    # Process each WordPress installation
    while IFS= read -r WP_PATH; do
        echo -e "\n${GREEN}[+] Processing WordPress installation: $WP_PATH${NC}"
        echo "================================================================"
        
        # Create backup
        backup_wordpress "$WP_PATH"
        
        # Check version
        if check_wp_version "$WP_PATH"; then
            # Vulnerable version detected
            update_wordpress "$WP_PATH"
        fi
        
        # Security checks
        detect_webshells "$WP_PATH"
        check_core_integrity "$WP_PATH"
        harden_uploads "$WP_PATH"
        
        echo "================================================================"
        
    done <<< "$WP_INSTALLS"
    
    echo -e "\n${GREEN}[+] Remediation complete!${NC}"
    echo -e "${YELLOW}[*] Next steps:${NC}"
    echo -e "${YELLOW}    1. Review backup directory for any files that need investigation${NC}"
    echo -e "${YELLOW}    2. Monitor logs for exploitation attempts: tail -f /var/log/apache2/access.log | grep wp-admin${NC}"
    echo -e "${YELLOW}    3. Consider implementing Web Application Firewall (WAF) rules${NC}"
    echo -e "${YELLOW}    4. Enable automatic WordPress updates: add_filter('auto_update_core', '__return_true');${NC}"
    echo ""
}

main "$@"

# Using WP-CLI (recommended)
wp core update
wp core update-db

# Verify update
wp core version

<Files *.php>
    Order Deny,Allow
    Deny from all
</Files>
RemoveHandler .php .phtml .php3
RemoveType .php .phtml .php3

# WordPress directories
find /var/www/html -type d -exec chmod 755 {} \;
find /var/www/html -type f -exec chmod 644 {} \;

# wp-config.php should be more restrictive
chmod 600 /var/www/html/wp-config.php

define('DISALLOW_FILE_EDIT', true);
define('DISALLOW_FILE_MODS', true); // Prevents plugin/theme installation from admin

// In wp-config.php or functions.php
add_filter('auto_update_core', '__return_true');
add_filter('allow_minor_auto_core_updates', '__return_true');
add_filter('allow_major_auto_core_updates', '__return_true'); // Optional, test first

# Example AIDE configuration
/var/www/html/wp-includes R+i
/var/www/html/wp-admin R+i
/var/www/html/wp-content/uploads p+i+n+u+g