CVE-2026-7748
Published: 04 May 2026
Summary
CVE-2026-7748 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Notion (inferred from references). Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 36.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-7748 is a buffer overflow vulnerability affecting the Totolink N300RH router on firmware version 3.2.4-B20220812, published on 2026-05-04. The flaw resides in the setUpgradeFW function within the /cgi-bin/cstecgi.cgi file, part of the POST Request Handler component. Manipulating the FileName argument triggers the buffer overflow, classified under CWE-119 and CWE-120.
The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating it is exploitable remotely over the network with low complexity and low privileges required, without user interaction. An attacker with low-privilege access can achieve high impacts on confidentiality, integrity, and availability, potentially leading to remote code execution via the buffer overflow.
Advisories and further details are documented in references such as VulDB entries (vuldb.com/vuln/360923 and related pages) and a public exploit proof-of-concept at lavender-bicycle-a5a.notion.site/TOTOLINK-N300RH-setUpgradeFW-34553a41781f80abb1d1c627d7ff4329. The vendor site at www.totolink.net provides additional context.
The exploit has been made publicly available and could be used for attacks.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26939
Vulnerability details
A weakness has been identified in Totolink N300RH 3.2.4-B20220812. Affected by this issue is the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. Executing a manipulation of the argument FileName can lead to buffer overflow. The…
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attack can be launched remotely. The exploit has been made available to the public and could be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in the router's internet-facing CGI endpoint (/cgi-bin/cstecgi.cgi setUpgradeFW) directly enables remote code execution against a public-facing application with no user interaction required.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the buffer overflow flaw in the setUpgradeFW function of the Totolink N300RH firmware by identifying, testing, and deploying patches.
Requires validation of the FileName argument in POST requests to the /cgi-bin/cstecgi.cgi handler to prevent buffer overflows from malformed inputs.
Implements memory safeguards such as stack canaries or DEP to protect against code execution from the buffer overflow exploitation.