CVE-2026-102139: CWE-639 Authorization Bypass Through User-Controlled Key in Kiteworks Email Protection Gateway
CVE-2026-102139 is an authorization bypass vulnerability in the large file exchange feature of Kiteworks Email Protection Gateway. It allows an authenticated user to access email package contents, including subject, message body, and attachments, of packages they neither sent nor received. This issue arises because the authorization check does not properly verify that the requesting user is a party to the requested package. The vulnerability affects versions prior to 9.5.1.
AI Analysis
Technical Summary
The vulnerability in Kiteworks Email Protection Gateway's large file exchange feature is due to an improper authorization check that fails to confirm the requesting user's association with the email package. As a result, an authenticated user with access to this optional feature can read sensitive information from packages they are not authorized to access. The CVSS 3.1 base score is 6.5, indicating a medium severity impact with network attack vector, low attack complexity, and requiring privileges but no user interaction. The confidentiality impact is high, while integrity and availability impacts are none.
Potential Impact
An authenticated user of the large file exchange feature can read the subject, message body, and attachments of email packages they did not send or receive, leading to unauthorized disclosure of potentially sensitive information. There is no impact on integrity or availability.
Mitigation Recommendations
No official patch or remediation information is provided in the available data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the large file exchange feature to trusted users only and monitor for unauthorized access attempts.
CVE-2026-102139: CWE-639 Authorization Bypass Through User-Controlled Key in Kiteworks Email Protection Gateway
Description
CVE-2026-102139 is an authorization bypass vulnerability in the large file exchange feature of Kiteworks Email Protection Gateway. It allows an authenticated user to access email package contents, including subject, message body, and attachments, of packages they neither sent nor received. This issue arises because the authorization check does not properly verify that the requesting user is a party to the requested package. The vulnerability affects versions prior to 9.5.1.
CVSS v3.1
Score 6.5medium
Affected software
Kiteworks
Email Protection Gateway
pkg:github/kiteworks/email-protection-gatewayRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in Kiteworks Email Protection Gateway's large file exchange feature is due to an improper authorization check that fails to confirm the requesting user's association with the email package. As a result, an authenticated user with access to this optional feature can read sensitive information from packages they are not authorized to access. The CVSS 3.1 base score is 6.5, indicating a medium severity impact with network attack vector, low attack complexity, and requiring privileges but no user interaction. The confidentiality impact is high, while integrity and availability impacts are none.
Potential Impact
An authenticated user of the large file exchange feature can read the subject, message body, and attachments of email packages they did not send or receive, leading to unauthorized disclosure of potentially sensitive information. There is no impact on integrity or availability.
Mitigation Recommendations
No official patch or remediation information is provided in the available data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict access to the large file exchange feature to trusted users only and monitor for unauthorized access attempts.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- cisa-cg
- Date Reserved
- 2026-09-28T17:39:13.564Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6abd72512a4e24523d8ebe2d
Added to database: 09/30/2026, 20:34:25 UTC
Last enriched: 09/30/2026, 20:49:23 UTC
Last updated: 10/01/2026, 04:47:23 UTC
Views: 9
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