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VulnerabilityPublished Updated

CVE-2026-40514: SmarterTools SmarterMail · PRNG

Affects SmarterTools SmarterMailSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 100.0.9610 soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
SmarterTools Inc.SmarterMailAffected
  • <100.0.9610
Fixed in
  • 100.0.9610

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.

References

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