Cyber Resilience

CVE-2023-7095

CriticalPublic PoC

Published: 25 December 2023

Published
25 December 2023
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0933 92.9th percentile
Risk Priority 25 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2023-7095 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Totolink A7100Ru Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 7.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

Deeper analysis

A buffer overflow vulnerability tracked as CVE-2023-7095 affects the Totolink A7100RU router running firmware 7.4cu.2313_B20191024. The flaw exists in the main function of /cgi-bin/cstecgi.cgi when the component processes an HTTP POST request with the action=login parameter; unsanitized input supplied to the flag argument triggers the overflow, corresponding to CWE-120.

An unauthenticated attacker can send a crafted POST request over the network to exploit the issue remotely. Successful exploitation yields full control over the device, enabling arbitrary code execution or a denial-of-service condition, consistent with the CVSS 9.8 rating that reflects no required privileges or user interaction.

Public proof-of-concept code has been released, and the EPSS score rose from a low baseline to a peak of 0.1424 before receding to its current value of 0.0933, indicating measurable post-disclosure interest in the vulnerability.

EU & UK References

Vulnerability details

A vulnerability, which was classified as critical, has been found in Totolink A7100RU 7.4cu.2313_B20191024. Affected by this issue is the function main of the file /cgi-bin/cstecgi.cgi?action=login of the component HTTP POST Request Handler. The manipulation of the argument flag leads…

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to buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. VDB-248942 is the identifier assigned to this vulnerability.

CWE(s)

Related Threats

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?

Buffer overflow in the publicly accessible web login CGI (/cgi-bin/cstecgi.cgi?action=login) enables remote code execution via exploitation of a public-facing application.

Affected Assets

totolink
a7100ru firmware
7.4cu.2313_b20191024

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

References