SonicWall SonicOS Improper Access Control
CVE-2024-40766 is a critical improper access control vulnerability in SonicWall SonicOS affecting management access and, per later vendor updates, local SSL VPN user access paths. The issue affects SonicWall Firewall Gen 5 and Gen 6 devices, and Gen 7 devices running SonicOS 7.0.1-5035 and earlier. SonicWall’s advisory describes the flaw as enabling unauthorized resource access and, under specific conditions, causing the firewall to crash. Multiple supporting sources also characterize the issue as impacting SSL VPN authentication/access control, with later incident investigations tying successful compromises to environments where local credentials—especially migrated credentials from Gen 6 to Gen 7—remained usable and were not reset. Public reporting and government/vendor advisories indicate the vulnerability has been actively exploited in the wild, including by Akira ransomware operators, against unpatched or improperly remediated SonicWall appliances.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository purpose: a Python-based SonicWall “Security Audit Toolkit” plus a Docker CTF-style lab that simulates and (in solutions) exploits two critical SonicWall CVEs. Top-level structure: - sonicwall_audit.py: main orchestrator CLI that runs modules (ssl, cve, auth, web) against a target https://<host>:<port>, writes JSON/text reports to reports/. - validate_cves.py: standalone deep validators for CVE-2021-20038 and CVE-2024-53704 using non-destructive behavioral checks. - modules/: implementation of auditors/validators and report generation. - lab/: docker-compose lab with two containers: - cve-2021-20038: Apache + deliberately vulnerable 32-bit CGI binary /usr/lib/cgi-bin/sslvpnclient (and symlinks portal/welcome/etc). Protections disabled (no canary, execstack, no PIE, ASLR disabled in entrypoint) to make stack overflow exploitation feasible. - cve-2024-53704: Flask/Gunicorn SSLVPN simulator on 4433 with vulnerable swap cookie deserialization (conditional HMAC verification). - lab/exploits/: skeleton exploit templates (incomplete). - lab/solutions/: working exploits. Exploit capabilities present: 1) CVE-2024-53704 (auth bypass via cookie forgery): Working exploit forges a base64-encoded JSON session cookie named swap with {username, authenticated:true} and omits sig_version so the server skips HMAC verification. It then accesses /virtual-office/ and /dashboard to retrieve the flag. 2) CVE-2021-20038 (stack buffer overflow -> RCE): Working exploit crafts a URL-encoded query string payload to overflow a 4096-byte stack buffer in the CGI handler (strcpy of QUERY_STRING). Payload includes a NOP sled, null-free 32-bit x86 Linux shellcode that runs /bin//sh -c "cat /root/flag.txt", padding to offset 4100, and an attacker-chosen return address into the sled. Output is returned in the HTTP response body. Important distinction: the main toolkit modules and CVE validators are primarily scanners/validators and explicitly avoid destructive exploitation; the actual exploitation code is confined to the lab solution scripts intended for the local practice environment.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
157 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A previously patched SonicWall flaw referenced as an example of continued post-patch compromise risk due to poor credential hygiene, SSL VPN exposure, MFA configuration issues, and inadequate monitoring.
A SonicWall VPN vulnerability cited as an alternative access vector used in Akira intrusions.
An improper access control vulnerability affecting SonicWall SonicOS.
A critical SonicWall vulnerability (CVSS 9.8) in CISA KEV with documented ransomware use (Akira, Fog). In this specific February 2026 activity, it was not meaningfully triggered, supporting the assessment that the observed activity was primarily reconnaissance rather than exploitation.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.