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A720R Firmware CVE-2025-9303

HIGH
Buffer Overflow (CWE-119)
2025-08-21 cna@vuldb.com
7.4
CVSS 4.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.4 (HIGH). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.56%.

Exploit ScenarioDerived

A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application.

This Month Plan within 30 days. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

A security flaw has been discovered in TOTOLINK A720R 4.1.5cu.630_B20250509.cgi. Rated high severity (CVSS 7.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. A security flaw has been discovered in TOTOLINK A720R 4.1.5cu.630_B20250509.cgi. Performing manipulation of the argument desc results in buffer overflow. The attack is possible to be carried out remotely. The exploit has been released to the public and may be exploited. Affected products include: Totolink A720R Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.4 HIGH
CVSS: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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
PoC Detected
Oct 06, 2025 - 18:48 vuln.today
Public exploit code
CVE Published
Aug 21, 2025 - 15:15 nvd
HIGH 7.4

DescriptionCVE.org

A security flaw has been discovered in TOTOLINK A720R 4.1.5cu.630_B20250509. This issue affects the function setParentalRules of the file /cgi-bin/cstecgi.cgi. Performing manipulation of the argument desc results in buffer overflow. The attack is possible to be carried out remotely. The exploit has been released to the public and may be exploited.

Executive ViewAI

Why It Matters

Organizations using A security flaw face moderate risk from CVE-2025-9303, a buffer overflow vulnerability rated CVSS 7.4. Exploitation could allow attackers to corrupt memory, crash the application, or potentially execute arbitrary code. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates when available and consider compensating controls in the interim.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.6%
Top 32% exploitable
Exploit
POC
Public exploit code exists

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.6%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No

Priority Score

58
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +37
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Affected Products (CPE)CVE.org

cpe:2.3:o:totolink:a720r_firmware:4.1.5cu.630_b20250509:*:*:*:*:*:*:*
CVE-2021-35327 CRITICAL POC
9.8 Aug 05

A vulnerability in TOTOLINK A720R A720R_Firmware v4.1.5cu.470_B20200911 allows attackers to start the Telnet service, th

CVE-2021-35324 CRITICAL POC
9.8 Aug 05

A vulnerability in the Form_Login function of TOTOLINK A720R A720R_Firmware V4.1.5cu.470_B20200911 allows attackers to b

CVE-2021-27710 CRITICAL POC
9.8 Apr 14

Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmwar

CVE-2021-27708 CRITICAL POC
9.8 Apr 14

Command Injection in TOTOLINK X5000R router with firmware v9.1.0u.6118_B20201102, and TOTOLINK A720R router with firmwar

CVE-2025-60683 MEDIUM POC
6.5 Nov 13

A command injection vulnerability exists in the ToToLink A720R Router firmware V4.1.5cu.614_B20230630 within the sysconf

CVE-2022-36610 HIGH POC
7.8 Aug 29

TOTOLINK A720R V4.1.5cu.532_B20210610 was discovered to contain a hardcoded password for root at /etc/shadow.sample. Rat

CVE-2022-36456 HIGH POC
7.8 Aug 25

TOTOLink A720R V4.1.5cu.532_B20210610 was discovered to contain a command injection vulnerability via the username param

CVE-2021-35326 HIGH POC
7.5 Aug 05

A vulnerability in TOTOLINK A720R router with firmware v4.1.5cu.470_B20200911 allows attackers to download the configura

CVE-2021-35325 HIGH POC
7.5 Aug 05

A stack overflow in the checkLoginUser function of TOTOLINK A720R A720R_Firmware v4.1.5cu.470_B20200911 allows attackers

CVE-2022-38535 HIGH POC
7.2 Sep 15

TOTOLINK-720R v4.1.5cu.374 was discovered to contain a remote code execution (RCE) vulnerability via the setTracerouteCf

CVE-2022-38534 HIGH POC
7.2 Sep 15

TOTOLINK-720R v4.1.5cu.374 was discovered to contain a remote code execution (RCE) vulnerability via the setdiagnosicfg

CVE-2025-4270 MEDIUM POC
6.9 May 05

A vulnerability was found in TOTOLINK A720R 4.1.5cu.374. Rated medium severity (CVSS 6.9), this vulnerability is remotel

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