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Kiteworks Email Protection Gateway CVE-2026-102139

| EUVDEUVD-2026-90275 MEDIUM
Authorization Bypass Through User-Controlled Key (CWE-639)
2026-09-30 cisa-cg
6.5
CVSS 3.1 · Vendor: cisa-cg
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Severity by source

Vendor (cisa-cg) PRIMARY
6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
vuln.today AI
6.5 MEDIUM

Authenticated network user (PR:L) abuses missing object-level authorization with low complexity to read others' data; confidentiality-only, so I:N/A:N.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (cisa-cg).

CVSS VectorVendor: cisa-cg

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

Lifecycle Timeline

4
Metadata Corrected
Sep 30, 2026 - 21:40 vuln.today
tag: Microsoft Kiteworks
Analysis Generated
Sep 30, 2026 - 21:28 vuln.today
Patch available
Sep 30, 2026 - 21:04 EUVD
CVE Published
Sep 30, 2026 - 20:11 cve.org
MEDIUM 6.5

DescriptionCVE.org

An authorization check in the large file exchange feature of Kiteworks Email Protection Gateway did not correctly establish that the requesting user was a party to the package being requested. An authenticated user of that optional feature could read the subject, message body, and attachments of packages they neither sent nor received.

AnalysisAI

Authenticated users of Kiteworks Email Protection Gateway versions before 9.5.1 can read the subject, message body, and attachments of large file exchange packages they neither sent nor received. Exploitation requires a valid account (PR:L) and the optional large file exchange feature to be enabled and in use; no public exploit has been identified at time of analysis. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
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Delivery
technique details hidden
Exploit
technique details hidden
Execution
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Impact
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Vulnerability AssessmentAI

Exploitation Exploitation requires an authenticated account on the Kiteworks Email Protection Gateway (PR:L) AND the optional 'large file exchange' feature to be enabled and in use - the description explicitly scopes the flaw to 'that optional feature.' Given those, a network attacker with low complexity and no user interaction reads the subject, body, and attachments of packages they neither sent nor received by manipulating the package reference. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment All signals converge on a moderate, not urgent, priority. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation Upgrade to Kiteworks Email Protection Gateway version 9.5.1 or later; this is the vendor-released patch that remediates the authorization flaw. … Detailed patch versions, workarounds, and compensating controls in full report.

Threat intelligence, references, and detailed analysis are available after sign-in.

CVE-2026-102115 CRITICAL
9.8 Sep 30

Unauthenticated attackers who know a target's email address can take over Kiteworks Core accounts that use locally store

CVE-2026-102149 CRITICAL
9.4 Sep 30

Improper certificate-assignment controls in Kiteworks Email Protection Gateway allow a remote, unauthenticated attacker

CVE-2026-102147 CRITICAL
9.3 Sep 30

Stored cross-site scripting in Kiteworks Core (all versions prior to 9.5.0) enables unauthenticated attackers to persist

CVE-2026-102106 CRITICAL
9.1 Sep 30

Authentication bypass in Kiteworks Email Protection Gateway (versions before 9.5.0) lets unauthenticated remote attacker

CVE-2026-102105 CRITICAL
9.1 Sep 30

Server-side request forgery in Kiteworks Email Protection Gateway (versions before 9.5.0) lets a remote, unauthenticated

CVE-2026-102095 CRITICAL
9.1 Sep 30

Server-side request forgery in Kiteworks Email Protection Gateway before 9.5.0 allows a remote, unauthenticated sender t

CVE-2026-102104 CRITICAL
9.1 Sep 30

Unauthenticated server-side request forgery in Kiteworks Email Protection Gateway before version 9.5.0 lets a remote att

CVE-2026-102103 CRITICAL
9.1 Sep 30

Server-side request forgery in Kiteworks Email Protection Gateway before 9.5.0 allows a remote, unauthenticated attacker

CVE-2026-102102 CRITICAL
9.1 Sep 30

Server-side request forgery in Kiteworks Email Protection Gateway (all versions before 9.5.0) lets a remote, unauthentic

CVE-2026-102120 HIGH
8.8 Sep 30

Command injection in Kiteworks Core's internal cluster-management function allows an attacker who already has code execu

CVE-2026-102125 HIGH
8.8 Sep 30

Sandbox escape in Kiteworks Core's document-conversion feature (CVE-2026-102125, CVSS 8.8) allows code already executing

CVE-2025-53939 HIGH
8.8 Nov 29

Authenticated privilege escalation in Kiteworks PDN (the Accellion-line private data network) before version 9.1.0 lets

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CVE-2026-102139 vulnerability details – vuln.today

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