CVE-2026-5104
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-2026-5104 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 15% 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-2026-5104 is a command injection vulnerability in the Totolink A3300R router running firmware version 17.0.0cu.557_b20221024. The flaw resides in the setStaticRoute function within the /cgi-bin/cstecgi.cgi script, where insufficient validation of the 'ip' argument allows attackers to inject arbitrary commands. This issue 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), indicating medium severity.
Remote attackers with low privileges, such as authenticated users, can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation enables limited impacts, including low-level disclosure of confidential information, modification of data or settings, and denial of service through partial availability disruption.
Advisories note that the exploit has been publicly disclosed, with proof-of-concept code available on GitHub at https://github.com/LvHongW/Vuln-of-totolink_A3300R/tree/main/A3300R_ip_cmd_inject. Additional details are documented on VulDB (https://vuldb.com/vuln/354129 and related pages), and the vendor's site is at https://www.totolink.net/, though no specific patch information is detailed in the provided references. Security practitioners should monitor for firmware updates and restrict access to the affected CGI endpoint.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17054
Vulnerability Data
A security vulnerability has been detected in Totolink A3300R 17.0.0cu.557_b20221024. Impacted is the function setStaticRoute of the file /cgi-bin/cstecgi.cgi. Such manipulation of the argument ip leads to command injection. The attack may be performed from remote. The exploit has been…
more
disclosed publicly and may be used.
- 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.