CVE-2025-15542
📋 TL;DR
CVE-2025-15542 is a denial-of-service vulnerability in TP-Link VX800v v1.0 VoIP phones where improper handling of SIP INVITE messages allows attackers to flood the device, blocking all voice lines and preventing incoming calls. This affects organizations using these specific VoIP phones in their telephony infrastructure.
💻 Affected Systems
- TP-Link VX800v
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete disruption of voice communications for affected devices, potentially affecting business operations and emergency communications.
Likely Case
Temporary denial of service on voice lines until the attack stops or device is rebooted.
If Mitigated
Limited impact if devices are behind firewalls with SIP rate limiting and proper network segmentation.
🎯 Exploit Status
Exploitation requires only the ability to send SIP INVITE messages to the target device, which is trivial for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check TP-Link support site for latest firmware
Vendor Advisory: https://www.tp-link.com/us/support/faq/4930/
Restart Required: Yes
Instructions:
1. Visit TP-Link support site for VX800v. 2. Download latest firmware. 3. Upload firmware via device web interface. 4. Reboot device after installation.
🔧 Temporary Workarounds
SIP Rate Limiting
allConfigure network devices to limit SIP INVITE messages to vulnerable devices
Network Segmentation
allIsolate VoIP devices in separate VLAN with restricted access
🧯 If You Can't Patch
- Implement strict firewall rules to only allow SIP traffic from trusted sources
- Deploy SIP-aware intrusion prevention systems to detect and block flood attacks
🔍 How to Verify
Check if Vulnerable:
Check device firmware version in web interface (should show VX800v v1.0)Check Version:
No CLI command - check via web interface at device IP addressVerify Fix Applied:
Verify firmware version has been updated from v1.0 to patched version📡 Detection & Monitoring
Log Indicators:
- High volume of SIP INVITE messages in device logs
- Voice line status changes to 'blocked' or 'unavailable'
Network Indicators:
- Unusually high SIP traffic to VoIP devices
- SIP INVITE messages from unexpected sources
SIEM Query:
sip.method="INVITE" AND sip.to_device="VX800v" | stats count by src_ip | where count > threshold