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Threats / SonicWall / CVE-2024-40766
CVE-2024-40766 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

SonicWall SonicOS vulnerability

SonicWall SonicOS contains an improper access control vulnerability allowing unauthorized resource access and potential denial of service through firewall crashes.

Verdict

Today item, not a backlog item.

An access control flaw in SonicOS enables attackers to bypass authentication controls and access protected resources. The vulnerability has been exploited in active ransomware campaigns, indicating real-world weaponization and elevated risk to deployed firewalls.

CISA KEV Yes · 2024-09-093Ransomware use Flagged3EPSS 0.15694 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
66 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2024-09-09), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.15694 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: SonicWall, SonicOS. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-284 Improper Access Control — weakness family: Authorization / access control.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-284 · Improper Access ControlAuthorization / access control
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution not established

No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I exploit the access control weakness to bypass authentication and gain unauthorized access to firewall administrative functions or protected network resources.
Business
Attackers gain a foothold to conduct reconnaissance, lateral movement, or deploy ransomware payloads across the network perimeter.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I trigger conditions that cause the firewall to crash, disrupting network security controls and creating a window for follow-on attacks.
Business
Network availability is compromised, security monitoring is disabled, and attackers exploit the outage to infiltrate systems or exfiltrate data.
3

Lateral reach — past segmentation narrative 3

Attacker
I leverage the compromised firewall as a pivot point to access internal systems and deploy ransomware across the organization.
Business
Critical systems are encrypted, operations halt, and the organization faces extortion demands and potential regulatory penalties.
04

What to do

— defensible action
  • Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • 66 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Catalogued by sonicwall (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by sonicwallCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.