CVE-2026-4254 — AI Deep Analysis Summary

Q: What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: Stack-based buffer overflow in Tenda AC8 router. 💥 **Consequences**: Remote Code Execution (RCE), full system compromise, data theft, and total loss of availability due to high CVSS score.

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-121 (Stack-based Buffer Overflow). 🐛 **Flaw**: Improper handling of the `local_2c` parameter in the `/goform/SysToolChangePwd` endpoint.

Q: Who is affected? (Versions/Components)

📦 **Affected**: Tenda AC8 Router. 📅 **Versions**: Firmware v16.03.50.11 and all earlier versions. ⚠️ **Vendor**: Tenda (China).

Q: What can hackers do? (Privileges/Data)

🕵️ **Hackers Can**: Execute arbitrary code with root privileges. 📂 **Data Impact**: Full Confidentiality, Integrity, and Availability loss (C:H, I:H, A:H). No user interaction needed.

Q: Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: LOW. 🚫 **Auth**: None required (PR:N). 🌐 **Access**: Network vector (AV:N). 🎯 **Complexity**: Low (AC:L). Easy to exploit remotely.

Q: Is there a public Exp? (PoC/Wild Exploitation)

📜 **Public Exp**: Yes. 🔗 **Links**: GitHub PoC available (`tenda_ac8_v5`) and VDB entries (VDB-351212). ⚠️ **Status**: Active exploitation indicators exist.

Q: How to self-check? (Features/Scanning)

🔍 **Check**: Scan for HTTP requests to `/goform/SysToolChangePwd`. 📡 **Feature**: Look for Tenda AC8 devices running firmware <= 16.03.50.11. 🧪 **Test**: Send oversized payloads to `local_2c` parameter.

Q: Is it fixed officially? (Patch/Mitigation)

🔧 **Fix**: Update firmware to version > 16.03.50.11. 🏢 **Official**: Check Tenda official website (tenda.com.cn) for the latest secure patch. 🔄 **Action**: Immediate update recommended.

Q: Is it urgent? (Priority Suggestion)

🔥 **Urgency**: CRITICAL. 🚨 **Priority**: Patch IMMEDIATELY. CVSS 9.8 (Critical). High risk of automated worm-like propagation. Do not delay.

Updated May 06, 2026 CVSS 9.8 · Critical

This is a summary of the AI-generated 10-question deep analysis. The full version (longer answers, follow-up Q&A, related CVEs) requires login. Read the full analysis →

Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: Stack-based buffer overflow in Tenda AC8 router. 💥 **Consequences**: Remote Code Execution (RCE), full system compromise, data theft, and total loss of availability due to high CVSS score.

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-121 (Stack-based Buffer Overflow). 🐛 **Flaw**: Improper handling of the `local_2c` parameter in the `/goform/SysToolChangePwd` endpoint.

Q3Who is affected? (Versions/Components)

📦 **Affected**: Tenda AC8 Router. 📅 **Versions**: Firmware v16.03.50.11 and all earlier versions. ⚠️ **Vendor**: Tenda (China).

Q4What can hackers do? (Privileges/Data)

🕵️ **Hackers Can**: Execute arbitrary code with root privileges. 📂 **Data Impact**: Full Confidentiality, Integrity, and Availability loss (C:H, I:H, A:H). No user interaction needed.

Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: LOW. 🚫 **Auth**: None required (PR:N). 🌐 **Access**: Network vector (AV:N). 🎯 **Complexity**: Low (AC:L). Easy to exploit remotely.

Q6Is there a public Exp? (PoC/Wild Exploitation)

📜 **Public Exp**: Yes. 🔗 **Links**: GitHub PoC available (`tenda_ac8_v5`) and VDB entries (VDB-351212). ⚠️ **Status**: Active exploitation indicators exist.

Q7How to self-check? (Features/Scanning)

🔍 **Check**: Scan for HTTP requests to `/goform/SysToolChangePwd`. 📡 **Feature**: Look for Tenda AC8 devices running firmware <= 16.03.50.11. 🧪 **Test**: Send oversized payloads to `local_2c` parameter.

Q8Is it fixed officially? (Patch/Mitigation)

🔧 **Fix**: Update firmware to version > 16.03.50.11. 🏢 **Official**: Check Tenda official website (tenda.com.cn) for the latest secure patch. 🔄 **Action**: Immediate update recommended.

Q9What if no patch? (Workaround)

🛑 **Workaround**: Block external access to `/goform/SysToolChangePwd` via firewall rules. 🚫 **Disable**: If possible, disable remote management features to reduce attack surface.…

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Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: CRITICAL. 🚨 **Priority**: Patch IMMEDIATELY. CVSS 9.8 (Critical). High risk of automated worm-like propagation. Do not delay.

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Vulnerability detail Full AI analysis (login) Tenda CWE-121