# CVE-2026-102143: Kiteworks Email Protection Gateway unauthenticated file upload

Source: https://junglewise.ai/threats/cve-2026-102143-an-unauthenticated-attacker-could-cause-a-file-with-attacker  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-30. Updated: 2026-09-30  
License: CC BY 4.0 with a link back

CVE-2026-102143 · Severity: high · CVSS 7.5 · Published 2026-09-30

Kiteworks Email Protection Gateway, which protects corporate email communications, contains an authentication bypass flaw in its administrative file upload handler. An attacker without credentials can upload files with arbitrary content to the appliance filesystem, potentially to prepare for further compromise. While the vulnerability itself does not enable direct code execution, it could be chained with other flaws to gain control of the system.

Technologies: [Kiteworks Email Protection Gateway](https://junglewise.ai/threats/technologies/email-protection-gateway). Vendors: [Kiteworks](https://junglewise.ai/threats/vendors/kiteworks).

## Quick answers

**Is CVE-2026-102143 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-102143 being exploited in the wild.

**How severe is CVE-2026-102143?** High severity, with a CVSS score of 7.5, published 30 September 2026.

**Which products and versions are affected?** Kiteworks Email Protection Gateway before 9.5.1.

**Is there a fix for CVE-2026-102143?** A patch was published on 2026-09-30: version 9.5.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-102143 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-102143?** Check whether you run Kiteworks Email Protection Gateway at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The administrative upload handler in Kiteworks Email Protection Gateway prior to version 9.5.1 fails to authenticate upload requests, allowing any network-accessible attacker to write arbitrary files to the appliance filesystem without authentication. The vulnerability is classified as unrestricted file upload combined with missing authentication (CWE-306, CWE-434), with a network attack vector and low complexity. Exploitation requires no privileges or user interaction; the attacker must be network-adjacent to the appliance but gains the ability to place files for potential code execution via a secondary vulnerability.

## Affected products

- Kiteworks Email Protection Gateway before 9.5.1

## Timeline

- 2026-09-30: disclosed
- 2026-09-30: patched: version 9.5.1

## References

- [https://github.com/kiteworks/security-advisories/security/advisories/GHSA-3p9g-jh62-8f89](https://github.com/kiteworks/security-advisories/security/advisories/GHSA-3p9g-jh62-8f89)
- [https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/VA/white/2026/va-26-274-01.json](https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/VA/white/2026/va-26-274-01.json)

## Related threats

- [Kiteworks Email Protection Gateway improper access control on certificate assignment](https://junglewise.ai/threats/cve-2026-102149-kiteworks-email-protection-gateway-did-not-sufficiently-restrict)
- [Kiteworks Email Protection Gateway arbitrary file write via template injection](https://junglewise.ai/threats/cve-2026-102146-an-authenticated-email-protection-gateway-administrator-holding)
- [Kiteworks Email Protection Gateway resource exhaustion](https://junglewise.ai/threats/cve-2026-102144-a-resource-exhaustion-vulnerability-in-kiteworks-email)
- [Kiteworks Email Protection Gateway authorization bypass in large file exchange](https://junglewise.ai/threats/cve-2026-102139-an-authorization-check-in-the-large-file-exchange-feature-of)
- [Kiteworks Email Protection Gateway deserialization of untrusted data](https://junglewise.ai/threats/cve-2026-102135-on-a-kiteworks-email-protection-gateway-cluster-with-database)