Cyber Posture

CVE-2026-31181

CriticalPublic PoC

Published: 23 April 2026

Published
23 April 2026
Modified
27 April 2026
KEV Added
—
Patch
—
CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0041 61.6th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Description

An issue was discovered in ToToLink A3300R firmware v17.0.0cu.557_B20221024 allowing attackers to execute arbitrary commands via the stunServerAddr parameter to /cgi-bin/cstecgi.cgi.

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match
prevent

Directly requires validation and sanitization of user inputs like the stunServerAddr parameter to prevent command injection attacks.

SI-2 Flaw Remediation good match
prevent

Mandates timely identification, reporting, and remediation of flaws such as the command injection vulnerability in the cstecgi.cgi script.

SI-9 Information Input Restrictions good match
prevent

Enforces restrictions on input types, formats, and quantities for parameters like stunServerAddr to block malicious command sequences.

Security SummaryAI

CVE-2026-31181 is a command injection vulnerability (CWE-78) discovered in ToToLink A3300R firmware version v17.0.0cu.557_B20221024. The issue resides in the /cgi-bin/cstecgi.cgi component, where the stunServerAddr parameter fails to properly sanitize user input, enabling attackers to inject and execute arbitrary operating system commands.

With a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), the vulnerability is exploitable remotely over the network by unauthenticated attackers requiring low complexity and no user interaction. Successful exploitation allows arbitrary command execution on the device, granting high-impact control over confidentiality, integrity, and availability, which could result in complete compromise of the affected router.

References point to GitHub repositories at https://github.com/Svigo-o/TOTOLINK-Vul/tree/main/totolink-a3300r-stun-server-addr-cmd-injection, which detail the vulnerability and likely include proof-of-concept code for reproduction and exploitation. No vendor advisories, patches, or official mitigation guidance are specified in the available information.

Details

CWE(s)
CWE-78

Affected Products

totolink
a3300r firmware
17.0.0cu.557_b20221024

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.
attack.mitre.org →
T1059.008 Network Device CLI Execution
Adversaries may abuse scripting or built-in command line interpreters (CLI) on network devices to execute malicious command and payloads.
attack.mitre.org →
Why these techniques?

Command injection in public-facing CGI endpoint (/cgi-bin/cstecgi.cgi) enables unauthenticated remote exploitation of public-facing application (T1190) leading to arbitrary OS command execution on network device (T1059.008).

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

References