Email Protection Gateway: Improper Restriction of XML External Entity Reference
CVE-2026-102127 is a high-severity improper restriction of XML external entity reference vulnerability in Email Protection Gateway from Kiteworks, with a CVSS 3.1 base score of 7.0 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 0.19% 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
- HighSuccess depends on conditions outside the attacker's control.
- 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
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:L. Scored by CNA.
Official description
An XML parser used by Kiteworks Email Protection Gateway did not restrict external entity references. Where an optional, non-default message-processing feature is enabled, a remote and unauthenticated sender could potentially use a crafted message to read files accessible to the gateway service account, including cryptographic key material and credentials, and have them sent to a destination they control.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How developers prevent this class of flaw
- Many XML parsers and validators can be configured to disable external entity expansion.
More Improper Restriction of XML External Entity Reference vulnerabilities (CWE-611)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, 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
- 7.5 High severity
- 7.2 High severity
Recent Improper Restriction of XML External Entity Reference vulnerabilities
- 7.7 High severity
- 7.7 High severity
- 9.3 Critical severity
- 7.7 High severity
- 7.4 High severity
- 7.4 High severity
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