Insufficient Data Verification in Tenda AC18 Firmware Upgrade Handler
CVE-2026-129258

9.4CRITICAL

Key Information:

Vendor

Tenda
Status
Ac18
Vendor
CVE Published:
14 November 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-129258?

A vulnerability has been identified in the Tenda AC18, specifically within the Firmware Upgrade Handler component located at /cgi-bin/upgrade. This flaw arises from insufficient verification of data authenticity due to a manipulation of the upgradeFile argument. As a result, attackers could potentially exploit this vulnerability remotely, leading to unauthorized actions. Public exploit methods are available, highlighting the importance of immediate attention to update firmware and secure the affected devices.

Affected Version(s)

AC18 15.03.05.05_multi

AC18 15.03.05.19 Build 6318

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-129258 - Proof of Concept

References

https://vuldb.com/vuln/437295
vdb-entrytechnical-description
https://vuldb.com/vuln/437295/cti
signaturepermissions-required
https://vuldb.com/cve/CVE-2026-129258
third-party-advisory

CVSS V4

Score:
9.4
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Longqxxixi (VulDB User)
.