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CVE-2026-51844: Tenda Ac7 Firmware Stack Buffer Overflow (CVSS 9.8)

CVE-2026-51844 is a critical severity stack buffer overflow in Tenda Ac7 Firmware with a CVSS score of 9.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 9, 2026

Quick answer

Direct answer

CVE-2026-51844 is a critical severity stack buffer overflow in Tenda Ac7 Firmware with a CVSS score of 9.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
9.8CRITICAL
EPSS probability
0.56%
Higher than 45 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:N)Network: reachable remotely
Attack complexity (AC:L)Low complexity
Privileges required (PR:N)No privileges required
User interaction (UI:N)No user interaction
Scope (S:U)Scope unchanged
Confidentiality (C:H)High confidentiality impact
Integrity (I:H)High integrity impact
Availability (A:H)High availability impact

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

About Tenda Ac7 Firmware

CVE-2026-51844 affects Tenda Ac7 Firmware, a product from Tenda. Before acting, confirm where Tenda Ac7 Firmware runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: Tenda AC7 v15.03.06.44 contains a stack buffer overflow vulnerability in the /goform/AdvSetMacMtuWan interface via the cloneType parameter.

The weakness class is Stack Buffer Overflow. A write past the end of a stack buffer can corrupt control data.

Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductTenda Ac7 Firmware
Affected versionsAc7 Firmware 15.03.06.44
PublishedJun 19, 2026
Last modifiedJul 9, 2026
Added to CISA KEVNot listed
Assigning CNAcve@mitre.org

How to detect it

  • Inventory every instance of Tenda Ac7 Firmware and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Tenda Ac7 Firmware named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Tenda Ac7 Firmware to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-51844 is a critical severity stack buffer overflow in Tenda Ac7 Firmware with a CVSS score of 9.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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A vulnerability was found in Tenda W3 1.0.0.3(2204). Affected by this issue is the function formSetCfm of the file /goform/setcfm of the component HTTP Handler. The manipulation of the argument funcpara1 results in stack-based buffer overflow. The attack can only be performed from the local network. The exploit has been made public and could be used.

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