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SmarterTools released an advisory for SmarterMail addressing vulnerabilities in versions prior to Build 9610, and government warning notices urged administrators to review the vendor guidance and apply the update. Germany's dCERT also published an advisory describing multiple vulnerabilities affecting the product, reinforcing the need for prompt remediation across exposed deployments.
One of the disclosed issues, CVE-2026-40514, is a cryptographic weakness in SmarterMail file and email sharing endpoints. The flaw stems from DES-CBC encryption using keys and IVs derived from System.Random, leaving an effective seed space of roughly 19,000 values; an unauthenticated attacker could use the attachment download endpoint as an oracle to recover the active seed, derive encryption material, and forge sharing tokens to access arbitrary emails, attachments, or stored files without prior authorization.
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2 events from the most recent confirmed update back to the earliest known activity.
The CVE-2026-40514 record states it was newly received by disclosure@vulncheck.com on April 27, 2026. The issue affects SmarterMail builds prior to 9610 and describes a weak-RNG cryptographic flaw in file and email sharing that could let an unauthenticated attacker forge sharing tokens.
SmarterTools published a security advisory on April 24, 2026 addressing a vulnerability in SmarterMail. The advisory indicates affected versions are builds prior to 9610 and directs users to update to remediate the issue.
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Multiple severe vulnerabilities in **SmarterMail** exposed internet-facing mail servers to compromise, including `CVE-2025-52691`, an unauthenticated arbitrary file upload flaw that can lead to immediate remote code execution, and `CVE-2026-23760`, an authentication bypass tied to the password reset API. Public reporting said `CVE-2025-52691` affected **Build 9406 and earlier**, carried a **CVSS 10.0** rating, and allowed attackers with network access to place files in arbitrary server locations and execute code with the privileges of the SmarterMail service. Advisories from Censys highlighted both issues, while a public GitHub proof-of-concept for `CVE-2026-23760` increased the risk of opportunistic exploitation. SmarterTools reportedly fixed the file upload vulnerability in **Build 9413**, with later builds available afterward, and security reporting warned that successful compromise of a mail gateway could expose customer email, credentials, and connected backend systems. The flaws were described as especially dangerous for hosting providers and organizations running exposed SmarterMail instances because they enable unauthenticated access paths that can quickly escalate to full server compromise.
Jun 29, 2026
A critical remote code execution (RCE) vulnerability, tracked as CVE-2025-52691, has been identified in SmarterMail, affecting Build 9406 and earlier. This flaw allows unauthenticated attackers to upload arbitrary files to any location on the mail server, enabling them to execute remote code and potentially gain full control over compromised systems. The vulnerability has been assigned a CVSS score of 10.0, indicating maximum severity, and poses a significant risk of unauthorized access, data exfiltration, malware deployment, and lateral movement within affected networks. SmarterTools has released Build 9413 to address this issue, and immediate patching is strongly advised to mitigate the threat. The vulnerability was discovered by Chua Meng Han from the Centre for Strategic Infocomm Technologies (CSIT), with responsible disclosure coordinated by the Cyber Security Agency (CSA) of Singapore. Security advisories from both SmarterTools and the Canadian Centre for Cyber Security urge all users and administrators to verify their SmarterMail version and apply the update to Build 9413 or later without delay. Failure to patch leaves organizations exposed to active exploitation and potential compromise of sensitive email communications and infrastructure.
Jun 29, 2026
A critical SmarterTools *SmarterMail* vulnerability, **CVE-2025-52691**, enables **remote code execution (RCE)** via an **unauthenticated arbitrary file upload** condition (CWE-434). The issue affects SmarterMail **Build 9406 and earlier** and is fixed in **Build 9413 and later**; the NVD lists a **CVSS v3.1 score of 10.0** (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`). Successful exploitation can allow full server compromise, including webshell deployment, data theft, and lateral movement under the service’s privileges. Internet-wide scanning reported **8,001 likely vulnerable IPs** out of **18,783** exposed SmarterMail instances (about **42.6%** failing checks), with the largest concentration in the **United States (~5,000)** followed by the **UK** and **Malaysia**. **Public proof-of-concept exploit code** is available, increasing the likelihood of opportunistic exploitation against unpatched, internet-facing deployments; multiple national agencies reportedly issued advisories following disclosure in late December 2025.
Jun 29, 2026