Cyber Posture

CVE-2025-28135

HighPublic PoC

Published: 27 March 2025

Published
27 March 2025
Modified
15 April 2025
KEV Added
Patch
CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0086 75.2th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-28135 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Totolink A810R Firmware. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 24.8% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Timely flaw remediation directly addresses the buffer overflow in downloadFile.cgi by applying firmware patches or updates for the TOTOLINK A810R.

prevent

Information input validation enforces bounds checking on CGI parameters to prevent buffer overflows from malicious network inputs.

prevent

Memory protection safeguards like stack canaries and non-executable stacks mitigate exploitation of the buffer overflow leading to device crashes.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Why these techniques?

Remote unauthenticated buffer overflow in web CGI component (downloadFile.cgi) of public-facing router enables exploitation of public-facing application for DoS impact.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

TOTOLINK A810R V4.1.2cu.5182_B20201026 was found to contain a buffer overflow vulnerability in downloadFile.cgi.

Deeper analysisAI

CVE-2025-28135 is a buffer overflow vulnerability, classified under CWE-121, affecting the TOTOLINK A810R router on firmware version V4.1.2cu.5182_B20201026. The flaw exists in the downloadFile.cgi component, as disclosed on March 27, 2025, with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

An unauthenticated remote attacker with network access to the device can exploit this vulnerability with low attack complexity and no user interaction required. Successful exploitation results in a denial-of-service condition, causing high availability impact through device crash or disruption, while confidentiality and integrity remain unaffected.

Advisories and additional details are available in the following references: https://github.com/Zerone0x00/CVE/blob/main/TOTOLINK/CVE-2025-28135.md and https://sudsy-eyeliner-a59.notion.site/BufferOverflow-V4-1-2cu-5182_B20201026-19872b8cd95f80808902fac8449fee64.

Details

CWE(s)

Affected Products

totolink
a810r firmware
4.1.2cu.5182_b20201026

CVEs Like This One

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CVE-2025-12260Same vendor: Totolink
CVE-2025-12241Same vendor: Totolink
CVE-2026-26732Same vendor: Totolink
CVE-2025-14964Same vendor: Totolink
CVE-2025-12258Same vendor: Totolink
CVE-2025-2370Same vendor: Totolink

References