Email Protection Gateway: Improper Authentication
CVE-2026-102128 is a high-severity improper authentication vulnerability in Email Protection Gateway from Kiteworks, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 9.5.1 as the first without the flaw, so updating Email Protection Gateway to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.21% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Email Protection Gateway to 9.5.1 or a later version.
- Update Kiteworks to 9.5.1 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Kiteworks | Email Protection Gateway | before 9.5.1 | 9.5.1 |
| Accellion | Kiteworks | before 9.5.1 | 9.5.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CNA.
Official description
An identity-verification weakness in Kiteworks Email Protection Gateway allowed the gateway to act on the Kiteworks platform on behalf of a user it had not authenticated, and to provision a platform account for an identity it did not already know. A remote, unauthenticated sender could potentially exploit this to obtain control of a platform account.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Email Protection Gateway
- 9.4 Critical severity
- 7.5 High severity
- 7.2 High severity
- 7.2 High severity
- 7.0 High severity
- 7.2 High severity
Recent Improper Authentication vulnerabilities
- 9.1 Critical severity
- 9.8 Critical severity
- 8.1 High severity
- 9.6 Critical severity
- 7.5 High severity
- 7.3 High severity
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