CVE-2025-65226Public exploit

HTTP service crash via unchecked deviceId copy

Published Nov 20, 2025 · Updated Nov 20, 2025

Heap buffer overflow in Tenda AC21 firmware 16.03.08.16 allows remote attackers to crash the HTTP service via crafted deviceId data. The saveParentControlInfo handler passes deviceId from webGetVar to strcpy, which copies it into a 0x254-byte heap allocation without checking its length. Exploitation requires access to the router's adjacent network but no authentication or user interaction, and the demonstrated consequence is an HTTP service crash.

CVSS severity4.3
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in Tenda AC21 firmware 16.03.08.16 allows remote attackers to crash the HTTP service via crafted deviceId data. The saveParentControlInfo handler passes deviceId from webGetVar to strcpy, which copies it into a 0x254-byte heap allocation without checking its length. Exploitation requires access to the router's adjacent network but no authentication or user interaction, and the demonstrated consequence is an HTTP service crash.

The record

CVE
CVE-2025-65226
Published
Nov 20, 2025
Updated
Nov 20, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 20, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

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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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Endpoint Denial of Service: Application 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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