CVE-2026-5102
Command Injection in Totolink A3300R Firmware 17.0.0cu.557_b20221024
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-5102 is a medium-severity Injection (CWE-74) vulnerability in Totolink A3300R Firmware. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 19% 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 map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-5102 is a command injection vulnerability in the Totolink A3300R router running firmware version 17.0.0cu.557_b20221024. The flaw resides in the setSmartQosCfg function within the /cgi-bin/cstecgi.cgi file of the Parameter Handler component, where manipulation of the qos_up_bw argument enables arbitrary command execution. It is classified under CWE-74 (Improper Neutralization of Special Elements) and CWE-77 (Command Injection), with a CVSS v3.1 base score of 6.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).
The vulnerability can be exploited remotely by attackers who possess low privileges, such as authenticated users on the device. Successful exploitation allows limited impacts on confidentiality, integrity, and availability, potentially enabling attackers to execute arbitrary commands on the underlying system without requiring user interaction.
References include a public exploit published on GitHub at https://github.com/Litengzheng/vul_db/blob/main/A3300R/vul_40/README.md, along with VulDB entries detailing the issue (https://vuldb.com/vuln/354127 and related pages). Security practitioners should consult the vendor's site at https://www.totolink.net/ for any available patches or firmware updates, as the exploit's public release increases the risk of active attacks.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17050
Vulnerability Data
A security flaw has been discovered in Totolink A3300R 17.0.0cu.557_b20221024. This vulnerability affects the function setSmartQosCfg of the file /cgi-bin/cstecgi.cgi of the component Parameter Handler. The manipulation of the argument qos_up_bw results in command injection. The attack can be executed…
more
remotely. The exploit has been released to the public and may be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover command-construction flaws before deployment.
SI-10 directly requires validation of information inputs to reject malformed or special-element content before it reaches downstream parsers.
Secure engineering principles include proper neutralization and safe command construction practices.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and output encoding that prevent injection flaws.
Runtime monitoring of software and data can detect anomalous command execution resulting from injection.
Identifying recorded vulnerabilities enables remediation of command-injection flaws before exploitation.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure coding standards require proper escaping and parameterization of commands, directly eliminating CWE-77.
Security testing in development catches injection vulnerabilities before release.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
Secure development life cycle mandates input validation and output encoding that directly prevent injection flaws.
Application security requirements explicitly call for controls against injection attacks in software design.