CVE-2025-13446Public exploitNetwork attack vector

Router crash via unchecked time parameters

Published Nov 20, 2025 · Updated Feb 24, 2026

Stack-based buffer overflow in Tenda AC21 firmware 16.03.08.16 allows remote authenticated users to crash the router via time settings. The fromSetSysTime handler passes timeZone data to unchecked strcpy and sscanf operations, while manual time input reaches sscanf without field-width limits. Access to the web management interface is required; published requests demonstrate a service crash, while code execution remains unconfirmed.

CVSS severity8.8
High
EPSS probability3.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in Tenda AC21 firmware 16.03.08.16 allows remote authenticated users to crash the router via time settings. The fromSetSysTime handler passes timeZone data to unchecked strcpy and sscanf operations, while manual time input reaches sscanf without field-width limits. Access to the web management interface is required; published requests demonstrate a service crash, while code execution remains unconfirmed.

The record

CVE
CVE-2025-13446
Published
Nov 20, 2025
Updated
Feb 24, 2026
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
AC21 Firmware
Classifications
CWE-121, CWE-119, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=16.03.08.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Shenzhen Tenda Technology Co., Ltd. · AC21 Firmwareversion=16.03.08.16

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.0VulDBAV:N/AC:L/Au:S/C:C/I:C/A:C
7.4VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
8.8VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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