Is CVE-2026-40514 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40514 being exploited in the wild.

How severe is CVE-2026-40514?

Medium severity, with a CVSS score of 5.9, published 27 April 2026.

Which products and versions are affected?

SmarterTools SmarterMail Prior to build 9610.

Is there a fix for CVE-2026-40514?

A patch was published on 2026-04-24: Build 9610 released to address the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-40514 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-40514?

Check whether you run SmarterTools SmarterMail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40514: SmarterTools SmarterMail cryptographic weakness in sharing endpoints

CVE-2026-40514 · Severity: medium · CVSS 5.9 · Published 2026-04-27

SmarterMail is an enterprise-grade email and collaboration server. A security flaw in how the system generates encryption keys for shared files and emails allows unauthorized individuals to bypass security controls. By exploiting this weakness, an attacker could gain access to private emails, attachments, and stored files without needing a password or prior access to the system.

Technologies: SmarterTools SmarterMail. Vendors: SmarterTools.

Quick answers

Is CVE-2026-40514 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40514 being exploited in the wild.
How severe is CVE-2026-40514?: Medium severity, with a CVSS score of 5.9, published 27 April 2026.
Which products and versions are affected?: SmarterTools SmarterMail Prior to build 9610.
Is there a fix for CVE-2026-40514?: A patch was published on 2026-04-24: Build 9610 released to address the issue. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-40514 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-40514?: Check whether you run SmarterTools SmarterMail at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

SmarterTools SmarterMail builds prior to 9610 utilize DES-CBC encryption for file and email sharing tokens. The keys and initialization vectors (IVs) for this encryption are derived from the System.Random class, which is seeded with insufficient entropy. This reduces the possible seed space to approximately 19,000 values. An unauthenticated remote attacker can use the attachment download endpoint as a decryption oracle to identify the active seed. Once the seed is determined, the attacker can derive the corresponding encryption keys and IVs to forge valid sharing tokens, granting unauthorized access to arbitrary emails, attachments, and file storage contents. The issue is resolved in SmarterMail build 9610.

Affected products

SmarterTools SmarterMail Prior to build 9610

Timeline

2026-04-24: patched: Build 9610 released to address the issue.
2026-04-27: disclosed: Initial vulnerability disclosure.
2026-04-27: advisory: NVD and VulnCheck advisories published.

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.