CVE-2026-40514: SmarterTools SmarterMail · PRNG
Affects SmarterTools SmarterMailSource CVE Database V5
Not known to be exploited · CVSS 8.2 High : upgrade to 100.0.9610 soon.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 100.0.9610
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 27 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 Oct 2026.
What to do
Upgrade SmarterTools SmarterMail to 100.0.9610.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| SmarterTools Inc.SmarterMail | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, restrict access to the affected endpoints and monitor for suspicious activity related to sharing token usage.
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.