CVE-2025-30256Network attack vector

Unauthenticated reboot via duplicate HTTP header allocation leak

Published Aug 20, 2025 · Updated Nov 3, 2025

Denial of service in Tenda AC6 V5.0 V02.03.01.110 HTTP header parsing allows remote attackers to reboot the router. The GoAhead websParseRequest function overwrites stored Cookie, Host, Authorization, or Accept-Language pointers after strdup without freeing earlier duplicate-header allocations. Unauthenticated delivery of repeated duplicate headers exhausts the RTOS device's memory, triggers an unhandled exception, and interrupts routing through a reboot.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Tenda AC6 V5.0 V02.03.01.110 HTTP header parsing allows remote attackers to reboot the router. The GoAhead websParseRequest function overwrites stored Cookie, Host, Authorization, or Accept-Language pointers after strdup without freeing earlier duplicate-header allocations. Unauthenticated delivery of repeated duplicate headers exhausts the RTOS device's memory, triggers an unhandled exception, and interrupts routing through a reboot.

The record

CVE
CVE-2025-30256
Published
Aug 20, 2025
Updated
Nov 3, 2025
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
AC6
Classifications
CWE-772, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record 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=V02.03.01.110

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shenzhen Tenda Technology Co., Ltd. · AC6version=V02.03.01.110

Published CVSS scores

8.6Cisco TalosCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
7.5NIST NVDCVSS: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

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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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