CVE-2026-5103
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:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-5103 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 Dynamic Linker Hijacking (T1574.006); ranked in the top 10% 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-2026-5103 is a command injection vulnerability (CWE-74, CWE-77) affecting the Totolink A3300R router in version 17.0.0cu.557_b20221024. The flaw exists in the setUPnPCfg function of the /cgi-bin/cstecgi.cgi file, where manipulation of the "enable" argument enables arbitrary command execution.
The vulnerability is exploitable remotely over the network with low complexity and low privileges required (PR:L), requiring no user interaction and maintaining unchanged scope. Attackers can achieve limited impacts on confidentiality, integrity, and availability, as reflected in its CVSS v3.1 base score of 6.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L). A public exploit is available, facilitating potential attacks.
Advisories referenced in VulDB entries (including submission and CTI details) document the issue, while a GitHub repository provides exploit code. The Totolink vendor website is also listed for further reference; practitioners should check these sources for any patch availability or mitigation guidance.
The exploit's public availability increases the risk of real-world attacks against unpatched Totolink A3300R devices.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17053
Vulnerability Data
A weakness has been identified in Totolink A3300R 17.0.0cu.557_b20221024. This issue affects the function setUPnPCfg of the file /cgi-bin/cstecgi.cgi. This manipulation of the argument enable causes command injection. The attack is possible to be carried out remotely. The exploit has…
more
been made available to the public and could 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.
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.
Secure SDLC practices directly require input validation and output encoding that prevent injection flaws.
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.
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.
Secure architecture principles reduce injection surfaces but do not prescribe specific neutralization techniques.
Secure coding standards require proper neutralization of special elements, directly addressing CWE-74.