CVE-2025-12611Public exploitNetwork attack vector

Service crash or code execution via unbounded sscanf

Published Nov 3, 2025 · Updated Nov 3, 2025

Stack-based buffer overflow in Tenda AC21 Firmware 16.03.08.16 allows remote attackers to crash its web service via a crafted startIp value. The formSetPPTPServer function passes the request value to sscanf with an unbounded %s conversion into fixed-size stack storage. The public proof of concept reaches the management endpoint without authentication; successful exploitation corrupts memory, crashes the service, or redirects execution.

CVSS severity9.8
Critical
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack-based buffer overflow in Tenda AC21 Firmware 16.03.08.16 allows remote attackers to crash its web service via a crafted startIp value. The formSetPPTPServer function passes the request value to sscanf with an unbounded %s conversion into fixed-size stack storage. The public proof of concept reaches the management endpoint without authentication; successful exploitation corrupts memory, crashes the service, or redirects execution.

The record

CVE
CVE-2025-12611
Published
Nov 3, 2025
Updated
Nov 3, 2025
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
AC21 Firmware
Classifications
CWE-119, CWE-120, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 3, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 privilegesunauthenticated

What is affected?

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

Published CVSS scores

9.0VulDB CNAAV:N/AC:L/Au:S/C:C/I:C/A:C
9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.4VulDB CNACVSS: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
8.8VulDB CNACVSS: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 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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo