Cyber Posture

CVE-2025-8136

HighPublic PoC

Published: 25 July 2025

Published
25 July 2025
Modified
28 July 2025
KEV Added
Patch
CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0063 70.3th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-8136 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Totolink A702R Firmware. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 29.7% 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) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

SI-10 requires validation of inputs like the ip6addr argument in HTTP POST requests to prevent buffer overflows by ensuring proper length and format checks.

prevent

SI-16 implements memory protections such as stack canaries, ASLR, and DEP to mitigate exploitation of buffer overflows even if invalid input reaches the vulnerable function.

prevent

SI-2 mandates timely identification, reporting, and patching of flaws like this buffer overflow vulnerability in router firmware to eliminate the root cause.

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.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
Why these techniques?

Buffer overflow in public-facing router web interface (/boafrm/formFilter) enables remote exploitation (T1190) and application/system DoS via crafted HTTP POST with ip6addr (T1499.004). PoC demonstrates DoS; critical impact on CIA suggests potential for broader abuse.

NVD Description

A vulnerability, which was classified as critical, was found in TOTOLINK A702R 4.0.0-B20230721.1521. Affected is an unknown function of the file /boafrm/formFilter of the component HTTP POST Request Handler. The manipulation of the argument ip6addr leads to buffer overflow. It…

more

is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

Deeper analysisAI

CVE-2025-8136 is a critical buffer overflow vulnerability (classified under CWE-119 and CWE-120) affecting the TOTOLINK A702R router running firmware version 4.0.0-B20230721.1521. The issue resides in an unknown function within the /boafrm/formFilter file of the HTTP POST Request Handler component. It is triggered by manipulating the ip6addr argument in a POST request, leading to a buffer overflow. The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and was published on 2025-07-25.

The vulnerability can be exploited remotely by an attacker who has low privileges (PR:L), such as an authenticated user on the device. No user interaction is required, and the low attack complexity enables straightforward exploitation over the network. Successful exploitation grants high-impact confidentiality, integrity, and availability consequences, potentially allowing arbitrary code execution or denial of service on the affected router.

Advisories and additional details are documented on VulDB (including ctiid.317532 and id.317532) and a GitHub repository detailing the exploit at github.com/panda666-888/vuls/blob/main/totolink/a702r/formFilter.md. The vendor's website at www.totolink.net is also referenced for potential patches or updates. The exploit has been publicly disclosed and may be actively used.

Details

CWE(s)

Affected Products

totolink
a702r firmware
4.0.0-b20230721.1521

CVEs Like This One

CVE-2025-8139Same product: Totolink A702R
CVE-2025-8138Same product: Totolink A702R
CVE-2025-8137Same product: Totolink A702R
CVE-2025-8140Same product: Totolink A702R
CVE-2025-9780Same product: Totolink A702R
CVE-2025-9783Same product: Totolink A702R
CVE-2025-9782Same product: Totolink A702R
CVE-2025-9779Same product: Totolink A702R
CVE-2025-9781Same product: Totolink A702R
CVE-2025-8245Same vendor: Totolink

References