CVE-2025-40604VulnerabilityPublished 20 Nov 2025Updated 26 Feb 2026

CVE-2025-40604: SonicWall Email Security · Download of Code Without Integrity Check

Affects SonicWall Email SecuritySource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

AI-suggested

To mitigate this vulnerability, organizations should immediately restrict and monitor access to virtualization datastores and VMDK files, ensuring only trusted administrators have such privileges. Implement strict role-based access controls (RBAC) and audit logging on virtualization management platforms to detect unauthorized access attempts. Apply network segmentation to isolate management interfaces and storage systems from general network access. Until a vendor patch or update is available, consider deploying additional host-based integrity monitoring on the appliance’s virtual disks to detect unauthorized modifications. Regularly back up appliance configurations and system images to enable recovery from compromise. Engage with SonicWall support for any available firmware updates or patches addressing this issue. Additionally, review and harden the virtualization environment’s security posture to reduce the risk of datastore compromise. Organizations should also consider deploying intrusion detection systems (IDS) and endpoint detection and response (EDR) solutions to identify suspicious activities related to virtualization infrastructure.

Description

Download of Code Without Integrity Check Vulnerability in the SonicWall Email Security appliance loads root filesystem images without verifying signatures, allowing attackers with VMDK or datastore access to modify system files and gain persistent arbitrary code execution.

Impact

If exploited, this vulnerability allows attackers with access to the virtualization infrastructure to implant persistent malicious code on SonicWall Email Security appliances. This can lead to unauthorized access to sensitive email data, manipulation or interception of email traffic, and potential lateral movement within the network. The integrity and confidentiality of the appliance and the data it processes are at risk. Although availability impact is rated low, the compromise of email security appliances can have significant operational and reputational consequences for organizations. The requirement for datastore or VMDK access limits the attack surface to environments where attackers have already penetrated virtualization management or storage layers, but in such cases, the impact can be severe. Organizations relying on SonicWall Email Security appliances in virtualized environments are particularly at risk, especially if virtualization infrastructure access controls are weak or compromised.

CWE-494Download of Code Without Integrity Check (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A08:2025: Software or Data Integrity Failures (opens in a new tab)
The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
Implementation
Perform proper forward and reverse DNS lookups to detect DNS spoofing.
Architecture and Design · Operation
Encrypt the code with a reliable encryption scheme before transmitting.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
XML Security (opens in a new tab)
Software Supply Chain Security (opens in a new tab)
Infrastructure as Code (opens in a new tab)
OWASP ASVS 4.0.3
V1.14.2 (opens in a new tab)
V10.3.1 (opens in a new tab)
V13.3.2 (opens in a new tab)
Attack patterns
Malicious Software Download (opens in a new tab)
Malicious Software Update (opens in a new tab)
Malicious Automated Software Update via Redirection (opens in a new tab)
Malicious Manual Software Update (opens in a new tab)
Open-Source Library Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

psirt.global.sonicwall.com/vuln-detail/SNWLID-2025-0018 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 27 Feb 2026, 06:41 UTC

WeaknessesCWE-494

Technical details

References

Community reviews

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