CVE-2026-2191
Published: 08 February 2026
Summary
CVE-2026-2191 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Tenda Ac9 Firmware. Its CVSS base score is 7.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 34.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.
Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.
Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.
Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Authenticated RCE via buffer overflow in public-facing router web interface directly maps to exploitation of a network-accessible application.
NVD Description
A weakness has been identified in Tenda AC9 15.03.06.42_multi. Affected is the function formGetDdosDefenceList. This manipulation of the argument security.ddos.map causes stack-based buffer overflow. The attack may be initiated remotely. The exploit has been made available to the public and…
more
could be used for attacks.
Deeper analysisAI
CVE-2026-2191 is a stack-based buffer overflow vulnerability affecting the Tenda AC9 router on firmware version 15.03.06.42_multi. The flaw resides in the formGetDdosDefenceList function, where manipulation of the security.ddos.map argument triggers the overflow. It is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-121 (Stack-based Buffer Overflow).
The vulnerability carries a CVSS v3.1 base score of 7.2 (AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H), indicating network-based exploitation with low attack complexity, no user interaction required, but high privileges (such as administrative access) needed. An attacker with sufficient privileges can remotely initiate the exploit to achieve high impacts on confidentiality, integrity, and availability, potentially leading to full device compromise.
Advisories reference a public exploit in a GitHub repository (https://github.com/glkfc/IoT-Vulnerability/blob/main/Tenda/tenda3.md) and multiple VulDB entries (https://vuldb.com/?ctiid.344894, https://vuldb.com/?id.344894, https://vuldb.com/?submit.749800), noting that the exploit is available for attacks. The Tenda vendor site (https://www.tenda.com.cn/) should be consulted for any patches or mitigation guidance.
The exploit has been made publicly available, increasing the risk of real-world attacks against vulnerable Tenda AC9 devices.
Details
- CWE(s)