Vulnerability in Smartertools Smartermail
CVE-2026-40514
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (16.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 16.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
Weakness classification (CWE)
References
- www.smartertools.com/smartermail/release-notes/current (release-notes, Release Notes, patch)
- www.vulncheck.com/advisories/smartertools-smartermail-build-9610-cryptographic-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-40514?
- CVE-2026-40514 is a medium-severity vulnerability in Smartertools Smartermail, classified under Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG). CVSS score: 5.9/10. Published 2026-04-27.
- How severe is CVE-2026-40514?
- Medium severity. CVSS v3 base score is 5.9 out of 10.