CVE-2026-4116
Published: 09 April 2026
Summary
CVE-2026-4116 is a high-severity Improper Handling of Unicode Encoding (CWE-176) vulnerability in Sonicwall Sma6210 Firmware. Its CVSS base score is 7.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Multi-Factor Authentication (T1556.006); 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-2 (Flaw Remediation).
Deeper analysis
CVE-2026-4116 is a vulnerability stemming from improper handling of Unicode encoding, classified under CWE-176, in SonicWall SMA1000 series appliances. It enables a remote authenticated SSLVPN user to bypass Time-based One-Time Password (TOTP) authentication for the Workplace/Connect Tunnel feature. 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 high severity due to its potential for significant impact on confidentiality, integrity, and availability.
Exploitation requires a remote attacker with high privileges, specifically an authenticated SSLVPN user account (PR:H). Once exploited over the network with low complexity and no user interaction, the attacker can circumvent TOTP protections for Workplace/Connect Tunnel access, potentially gaining unauthorized elevated access within the VPN environment and leading to high-impact compromise across the CIA triad.
SonicWall has documented the issue in their PSIRT advisory SNWLID-2026-0003, available at https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0003, which provides further details on affected versions and recommended mitigations.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-20908
Vulnerability details
Improper handling of Unicode encoding in SonicWall SMA1000 series appliances allows a remote authenticated SSLVPN user to bypass Workplace/Connect Tunnel TOTP authentication.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables bypassing TOTP MFA via flaw in authentication implementation, directly mapping to T1556.006.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the improper Unicode encoding handling (CWE-176) by requiring validation of inputs to the TOTP authentication process in the SSLVPN appliance.
Requires timely identification, reporting, and correction of the specific flaw enabling TOTP bypass in SonicWall SMA1000 series appliances.
Ensures receipt, dissemination, assessment, and response to the SonicWall PSIRT advisory SNWLID-2026-0003 for this vulnerability and its mitigations.