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CVE-2026-4254 β€” AI Deep Analysis Summary

CVSS 9.8 Β· Critical

Q1What is this vulnerability? (Essence + Consequences)

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

Q2Root Cause? (CWE/Flaw)

πŸ›‘οΈ **Root Cause**: CWE-121 (Stack-based Buffer Overflow). πŸ› **Flaw**: Improper handling of the `local_2c` parameter in the `/goform/SysToolChangePwd` endpoint.

Q3Who is affected? (Versions/Components)

πŸ“¦ **Affected**: Tenda AC8 Router. πŸ“… **Versions**: Firmware v16.03.50.11 and all earlier versions. ⚠️ **Vendor**: Tenda (China).

Q4What can hackers do? (Privileges/Data)

πŸ•΅οΈ **Hackers Can**: Execute arbitrary code with root privileges. πŸ“‚ **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)

πŸ“œ **Public Exp**: Yes. πŸ”— **Links**: GitHub PoC available (`tenda_ac8_v5`) and VDB entries (VDB-351212). ⚠️ **Status**: Active exploitation indicators exist.

Q7How to self-check? (Features/Scanning)

πŸ” **Check**: Scan for HTTP requests to `/goform/SysToolChangePwd`. πŸ“‘ **Feature**: Look for Tenda AC8 devices running firmware <= 16.03.50.11. πŸ§ͺ **Test**: Send oversized payloads to `local_2c` parameter.

Q8Is it fixed officially? (Patch/Mitigation)

πŸ”§ **Fix**: Update firmware to version > 16.03.50.11. 🏒 **Official**: Check Tenda official website (tenda.com.cn) for the latest secure patch. πŸ”„ **Action**: Immediate update recommended.

Q9What if no patch? (Workaround)

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

Q10Is it urgent? (Priority Suggestion)

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