CVE-2026-25067VulnerabilityPublished 29 Jan 2026Updated 5 Mar 2026

CVE-2026-25067: SmarterTools SmarterMail · Use of Incorrectly-Resolved Name or Reference

Affects SmarterTools SmarterMailSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium : upgrade to 100.0.9518 when convenient.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 100.0.9518

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system 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 Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 Jan 2026
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 26 Oct 2026.

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

Upgrade SmarterTools SmarterMail to 100.0.9518.

Affected software

Product	Affected	Fixed in
SmarterToolsSmarterMail	Affected <100.0.9518	Fixed in 100.0.9518

AI-suggested

Organizations should immediately audit their SmarterMail deployments to identify versions prior to build 9518 and prioritize upgrading to the latest patched version once available. In the absence of an official patch, administrators can implement network-level controls to restrict outbound SMB traffic from SmarterMail servers, such as firewall rules blocking SMB ports (TCP 445 and 139) to untrusted networks. Additionally, disabling or restricting the background-of-the-day preview feature may reduce exposure. Monitoring network traffic for unusual SMB authentication attempts originating from SmarterMail servers can help detect exploitation attempts. Employing SMB signing and enforcing strong authentication policies can mitigate NTLM relay risks. Network segmentation to isolate mail servers and limiting their access to only necessary resources further reduces potential impact. Regularly reviewing and hardening Windows SMB configurations and applying principle of least privilege to service accounts running SmarterMail are also recommended to limit damage if exploitation occurs.

Description

SmarterTools SmarterMail versions prior to build 9518 contain an unauthenticated path coercion vulnerability in the background-of-the-day preview endpoint. The application base64-decodes attacker-supplied input and uses it as a filesystem path without validation. On Windows systems, this allows UNC paths to be resolved, causing the SmarterMail service to initiate outbound SMB authentication attempts to attacker-controlled hosts. This can be abused for credential coercion, NTLM relay attacks, and unauthorized network authentication.

Impact

The primary impact of this vulnerability is the potential for credential theft and unauthorized network authentication through SMB protocol abuse. Attackers can coerce the SmarterMail service into authenticating to attacker-controlled SMB servers, capturing NTLM hashes or relaying them to other network services, facilitating lateral movement and privilege escalation within corporate networks. This can lead to compromise of sensitive email data, disruption of mail services, and broader network breaches. Organizations relying on SmarterMail for email infrastructure, especially those with Windows-based deployments, face increased risk of internal network compromise. The unauthenticated nature of the vulnerability means attackers can exploit it remotely without prior access, increasing the attack surface. Although the confidentiality impact is limited to credential exposure and potential relay attacks, the integrity and availability of email services could be indirectly affected through subsequent attacks leveraging stolen credentials.

CWE-706Use of Incorrectly-Resolved Name or Reference (opens in a new tab)
Class weaknessOWASP Top 10 A01:2021: Broken Access Control (opens in a new tab)
The product uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.
Attack patterns
Redirect Access to Libraries (opens in a new tab)
Create files with the same name as files protected with a higher classification (opens in a new tab)
Passing Local Filenames to Functions That Expect a URL (opens in a new tab)
DLL Side-Loading (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Mar 2026, 09:22 UTC

WeaknessesCWE-706

Technical details

References

Community reviews

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