CVE-2026-40514 SmarterTools SmarterMail < Build 9610 Cryptographic Weakness via Weak RNG

What is CVE-2026-40514?

CVE-2026-40514 is a high-severity vulnerability in SmarterTools Inc. SmarterMail, published on 27 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

SmarterTools SmarterMail builds prior to 9610 contain a cryptographic weakness in the file and email sharing endpoints that use DES-CBC encryption with keys and initialization vectors derived from System.Random seeded with insufficient entropy, reducing the seed space to approximately 19,000 possible values. An unauthenticated attacker can use the attachment download endpoint as an oracle to determine the seed in use and derive encryption keys and initialization vectors to forge sharing tokens for arbitrary emails, attachments, or file storage contents without prior access to the targeted content.

Weakness: CWE-338

Which versions are affected by CVE-2026-40514?

It affects 1 product.

Products include Smartertools Smartermail.

How do I fix CVE-2026-40514?

No fix has been published for CVE-2026-40514 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-40514 being exploited?

There is no known exploitation of CVE-2026-40514 in the wild and no public exploit code.

Other vulnerabilities in SmarterTools Inc. SmarterMail

• CVE-2025-52691 SmarterTools SmarterMail Unrestricted Upload of File with Dangerous Type Exploited Critical 10.0
• CVE-2026-24423 SmarterTools SmarterMail Missing Authentication for Critical Function Exploited Critical 9.3
• CVE-2026-23760 SmarterTools SmarterMail Authentication Bypass Using an Alternate Path or Channel Exploited Critical 9.3
• CVE-2021-32234 Code injection in n/a Critical 9.8
• CVE-2019-7214 Deserialization in n/a Critical 9.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-j74m-34v4-rgqp.