CVE-2026-102139: Auth Bypass (CVSS 6.5)

Description

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.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-639 CWE-639

CWE-863 Incorrect Authorization

References

Other References

https://github.com/kiteworks/security-advisories/security/advisories/GHSA-fp46-xhg8-vpgm https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/VA/white/2026/va-26-274-01.json

Frequently Asked Questions

What is CVE-2026-102139? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-102139? +

CVE-2026-102139 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-102139? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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