CVE-2025-65220Public exploit

Service crash via unbounded list parsing

Published Nov 20, 2025 · Updated Nov 20, 2025

A stack-based buffer overflow in Tenda AC21 16.03.08.16 allows remote attackers to crash the web service through a crafted HTTP POST request. The /bin/httpd formSetVirtualSer handler passes the list parameter to save_virtualser_data, where unbounded sscanf conversions write past stack buffers. No authentication or user interaction is required, but access is limited to an adjacent network; demonstrated impact is a segmentation fault and service crash.

CVSS severity4.3
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A stack-based buffer overflow in Tenda AC21 16.03.08.16 allows remote attackers to crash the web service through a crafted HTTP POST request. The /bin/httpd formSetVirtualSer handler passes the list parameter to save_virtualser_data, where unbounded sscanf conversions write past stack buffers. No authentication or user interaction is required, but access is limited to an adjacent network; demonstrated impact is a segmentation fault and service crash.

The record

CVE
CVE-2025-65220
Published
Nov 20, 2025
Updated
Nov 20, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-121, 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-121Stack-based Buffer Overflow
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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