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Security Bulletin: Boundary Workers Vulnerable to Denial of Service During TLS Handshake

Security Bulletin


Summary

Boundary Community Edition and Boundary Enterprise (“Boundary”) workers are vulnerable to a denial-of-service condition during node enrollment TLS handshakes. An attacker with network access to the worker authentication listener may open a connection and delay or withhold the client certificate during the TLS handshake, causing worker connection handling to block. This may prevent legitimate worker connections from being accepted or routed. This vulnerability, CVE-2026-7776, is fixed in Boundary 0.21.3, 0.20.3, 0.19.5.

Vulnerability Details

CVEID: CVE-2026-7776
DESCRIPTION: Boundary’s node enrollment dependency performed the server-side TLS handshake synchronously while accepting and classifying worker connections. A client that connected to the worker authentication listener and then stalled during the TLS handshake, including by delaying or not providing a requested client certificate, could block the connection handling path. This could cause later legitimate worker connections to be delayed or prevented from completing, resulting in a denial of service for worker authentication and enrollment workflows. The issue requires network-level access to the affected listener, but does not require successful authentication.
CWE: CWE-770: Allocation of Resources Without Limits or Throttling
CVSS Source: HashiCorp Inc.
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

Affected Product(s)Version(s)
Boundary Community Editionaffected from 0.9.0 up to 0.21.3, unaffected from 0.19.5, 0.20.3, 0.21.3
Boundary Enterpriseaffected from 0.9.0 up to 0.21.3, unaffected from 0.19.5, 0.20.3, 0.21.3

Remediation/Fixes

Customers should evaluate the risk associated with this issue and consider upgrading to Boundary Community Edition or Boundary Enterprise 0.21.3, 0.20.3, 0.19.5. Please refer to Boundary’s upgrade documentation for general guidance: https://developer.hashicorp.com/boundary/docs/upgrading

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References

Off

Acknowledgement

This issue was identified by the Boundary Engineering team.

Change History

04 May 2026: Initial Publication

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.

Disclaimer

According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.

Document Location

Worldwide

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Document Information

Modified date:
04 May 2026

Initial Publish date:
04 May 2026

UID

ibm17271691