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A800R Firmware CVE-2025-28136

MEDIUM
Stack-based Buffer Overflow (CWE-121)
2025-04-15 cve@mitre.org
6.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

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A06:2021 - Vulnerable and Outdated Components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

1 technique across 1 tactic: Execution

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

Impact

CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.22%.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

TOTOLINK A800R V4.1.2cu.5137_B20200730 was found to contain a buffer overflow vulnerability in the downloadFile.cgi. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

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 under CWE-121. TOTOLINK A800R V4.1.2cu.5137_B20200730 was found to contain a buffer overflow vulnerability in the downloadFile.cgi. Affected products include: Totolink A800R Firmware.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionCVE.org

TOTOLINK A800R V4.1.2cu.5137_B20200730 was found to contain a buffer overflow vulnerability in the downloadFile.cgi.

Executive ViewAI

Why It Matters

Organizations using TOTOLINK A800R V4.1.2cu.5137_B20200730 should be aware of notable risk from CVE-2025-28136, a stack-based buffer overflow vulnerability rated CVSS 6.5. Exploitation could cause memory corruption or application crashes. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Moderate
Compensating Controls

Apply vendor patch. If patching is delayed: enable ASLR/DEP, apply network segmentation.

Threat Intelligence Overview

EPSS Score
0.2%
Top 55% exploitable
Data Quality
4 sources
Confidence: Medium

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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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
None
System Exposure· derived
Open
Automatable· derived
Yes

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
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.

A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.

Affected Products (CPE)CVE.org

cpe:2.3:o:totolink:a800r_firmware:4.1.2cu.5137_b20200730:*:*:*:*:*:*:*
CVE-2025-28138 CRITICAL POC
9.8 Mar 27

The TOTOLINK A800R V4.1.2cu.5137_B20200730 were found to contain a pre-auth remote command execution vulnerability in th

CVE-2025-28036 CRITICAL POC
9.8 Apr 22

TOTOLINK A950RG V4.1.2cu.5161_B20200903 was found to contain a pre-auth remote command execution vulnerability in the se

CVE-2025-28035 CRITICAL POC
9.8 Apr 22

TOTOLINK A830R V4.1.2cu.5182_B20201102 was found to contain a pre-auth remote command execution vulnerability in the set

CVE-2025-28034 CRITICAL POC
9.8 Apr 22

TOTOLINK A800R V4.1.2cu.5137_B20200730, A810R V4.1.2cu.5182_B20201026, A830R V4.1.2cu.5182_B20201102, A950RG V4.1.2cu.51

CVE-2022-26214 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26212 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26211 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26210 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26209 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26208 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26207 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

CVE-2022-26206 CRITICAL POC
9.8 Mar 15

Totolink A830R V5.9c.4729_B20191112, A3100R V4.1.2cu.5050_B20200504, A950RG V4.1.2cu.5161_B20200903, A800R V4.1.2cu.5137

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