Cyber Resilience

CVE-2026-4116

Sonicwall Sma6210 Firmware ≤ 12.4.3-03387

Published
09 April 2026
Modified
14 May 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.2
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0042 35th percentile
Risk Priority 53 floored blend · peak EPSS

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 Invisible Unicode (T1027.018); ranked at the 35th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to 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-2026-4116 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

Vulnerability Data

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)
CWE-176

Related Threats

MITRE ATT&CK Enterprise Techniques

T1027.018 Invisible Unicode Stealth
Adversaries may abuse invisible or non-printing Unicode characters to conceal malicious content within files, scripts, or text.
attack.mitre.org →
T1027 Obfuscated Files or Information Stealth
Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit.
attack.mitre.org →
T1132 Data Encoding Command And Control
Adversaries may encode data to make the content of command and control traffic more difficult to detect.
attack.mitre.org →
T1132.002 Non-Standard Encoding Command And Control
Adversaries may encode data with a non-standard data encoding system to make the content of command and control traffic more difficult to detect.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-4114Same product: Sonicwall Sma6200
CVE-2026-4112Same product: Sonicwall Sma6200
CVE-2025-40602Same product: Sonicwall Sma6200
CVE-2026-4113Same product: Sonicwall Sma6200
CVE-2025-23006Same product: Sonicwall Sma6200
CVE-2026-15409Same product: Sonicwall Sma6210
CVE-2026-15410Same product: Sonicwall Sma6210
CVE-2026-20202Shared CWE-176
CVE-2026-35373Shared CWE-176
CVE-2025-55129Shared CWE-176

Affected Assets

sonicwall
sma6210 firmware
≤ 12.4.3-03387 · 12.5.0 — 12.5.0-02624
sonicwall
sma6200 firmware
≤ 12.4.3-03387 · 12.5.0 — 12.5.0-02624
sonicwall
sma7200 firmware
≤ 12.4.3-03387 · 12.5.0 — 12.5.0-02624
sonicwall
sma7210 firmware
≤ 12.4.3-03387 · 12.5.0 — 12.5.0-02624
sonicwall
sma8200v
≤ 12.4.3-03387 · 12.5.0 — 12.5.0-02624

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly requires checking and normalizing encodings so that Unicode is handled consistently before further processing.

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.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper Unicode/input validation to prevent this weakness.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect Unicode-handling flaws before deployment.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and encoding handling that can prevent Unicode mishandling.

A.8.26 Application security requirements partial match
prevents

Application security requirements include proper handling of character encodings and input sanitization.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles require robust input processing to avoid encoding-related vulnerabilities.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address proper Unicode and character-encoding validation.

References