SonicWall SonicOS Flaws Bypass Access & Crash Firewall

SonicWall has issued a new security advisory detailing three vulnerabilities impacting its SonicOS software.

Discovered by the Advanced Research Team at CrowdStrike, these flaws could allow attackers to bypass access controls, reach restricted services, or cause a denial-of-service condition by crashing the firewall.

Administrators are urged to apply the latest firmware updates immediately to secure their networks against potential exploitation.

SonicWall SonicOS Vulnerabilities

The advisory outlines three distinct vulnerabilities affecting various generations of SonicWall firewalls.

• CVE-2026-0204 is an improper access control flaw with a CVSS score of 8.0, allowing attackers to access certain management interface functions under specific conditions due to weak authentication.
• CVE-2026-0205 is a post-authentication path-traversal vulnerability with a CVSS score of 6.8, enabling an attacker to access services that are usually restricted.
• CVE-2026-0206 is a post-authentication stack-based buffer overflow with a CVSS score of 4.9, permitting a remote attacker to crash the firewall device.

These vulnerabilities impact a wide range of SonicWall hardware and virtual firewalls across Generation 6, 7, and 8 product lines.

• Generation 6 hardware firewalls running version 6.5.5.1-6n and older are vulnerable.
• Generation 7 firewalls running versions 7.0.1-5169 or 7.3.1-7013, or earlier, are affected.
• Generation 7 NSv virtual platforms are impacted on versions 7.0.1-5169 and 7.3.1-7013 or older.
• Generation 8 firewalls running version 8.1.0-8017 and older require patching.

SonicWall has released fixed firmware versions to resolve these security issues.

Administrators should upgrade to version 6.5.5.2-28n for Gen6 devices, 7.3.2-7010 for Gen7 devices, and 8.2.0-8009 for Gen8 devices.

If immediate patching is not possible, SonicWall strongly recommends implementing a temporary workaround to protect exposed devices.

You should completely disable HTTP and HTTPS-based firewall management as well as SSLVPN on all interfaces.

To maintain administrative control, restrict management access exclusively to SSH until you can apply the appropriate firmware updates.

Warning for Gen6 Devices

Organizations operating Generation 6 firewalls must exercise caution when updating to the fixed version 6.5.5.2-28n.

SonicWall explicitly warns against downgrading from this patched firmware to any previous version.

Performing a firmware downgrade on Gen6 devices will result in the deletion of all LDAP users and a complete reset of all Multi-Factor Authentication configurations.

If a downgrade becomes necessary, administrators will need to reconfigure all LDAP and MFA settings afterward manually.

Always perform a full configuration backup before beginning the upgrade process to prevent data loss.

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