CVE-2023-39786Public exploitNetwork attack vector

Router crash via unbounded time parsing

Published Aug 21, 2023 · Updated Jul 9, 2026

Stack overflow in Tenda AC8v4 firmware 16.03.34.06 allows remote attackers to crash the router via a crafted time parameter. The /goform/PowerSaveSet handler passes the request's time value from websGetVar to sscanf without field-width limits, overflowing four stack buffers. No authentication or user interaction is required; the published proof of concept demonstrates a denial-of-service crash rather than code execution.

CVSS severity7.5
High
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack overflow in Tenda AC8v4 firmware 16.03.34.06 allows remote attackers to crash the router via a crafted time parameter. The /goform/PowerSaveSet handler passes the request's time value from websGetVar to sscanf without field-width limits, overflowing four stack buffers. No authentication or user interaction is required; the published proof of concept demonstrates a denial-of-service crash rather than code execution.

The record

CVE
CVE-2023-39786
Published
Aug 21, 2023
Updated
Jul 9, 2026
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
Tenda AC8 Firmware
Classifications
CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 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=16.03.34.06

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shenzhen Tenda Technology Co., Ltd. · Tenda AC8 Firmwareversion=16.03.34.06

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

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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