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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://www.smartertools.com/smartermail/release-notes/current	Release Notes
https://www.vulncheck.com/advisories/smartertools-smartermail-build-9610-cryptographic-weakness-via-weak-rng	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:smartertools:smartermail:*:*:*:*:*:*:*:*

History

04 Jun 2026, 15:28

Type	Values Removed	Values Added
References	~~() https://www.smartertools.com/smartermail/release-notes/current -~~	() https://www.smartertools.com/smartermail/release-notes/current - Release Notes
References	~~() https://www.vulncheck.com/advisories/smartertools-smartermail-build-9610-cryptographic-weakness-via-weak-rng -~~	() https://www.vulncheck.com/advisories/smartertools-smartermail-build-9610-cryptographic-weakness-via-weak-rng - Third Party Advisory
CPE		cpe:2.3:a:smartertools:smartermail::::::::
First Time		Smartertools Smartertools smartermail

27 Apr 2026, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-04-27 15:16

Updated : 2026-06-04 15:28

NVD link : CVE-2026-40514

Mitre link : CVE-2026-40514

CVE.ORG link : CVE-2026-40514

JSON object : View

Products Affected

smartertools

smartermail

CWE

CWE-338

Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)

{"id": "CVE-2026-40514", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.9, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 3.6, "exploitabilityScore": 2.2}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.1, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.2, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2026-04-27T15:16:20.160", "references": [{"url": "https://www.smartertools.com/smartermail/release-notes/current", "tags": ["Release Notes"], "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/smartertools-smartermail-build-9610-cryptographic-weakness-via-weak-rng", "tags": ["Third Party Advisory"], "source": "disclosure@vulncheck.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-338"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-06-04T15:28:12.010", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:smartertools:smartermail:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "6D6A4497-F89B-4062-A995-6386B9ACC753", "versionEndExcluding": "100.0.9610"}], "operator": "OR"}]}], "sourceIdentifier": "disclosure@vulncheck.com"}