CVE-2026-7776
Published: 04 May 2026
Summary
CVE-2026-7776 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Hashicorp (inferred from references). Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 10.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability).
Deeper analysis
CVE-2026-7776 is a denial-of-service vulnerability affecting Boundary Community Edition and Boundary Enterprise workers from HashiCorp. The issue arises during node enrollment TLS handshakes on the worker authentication listener, where an attacker can open a connection and delay or withhold the client certificate. This causes the worker's connection handling to block, preventing legitimate worker connections from being accepted or routed. The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and is associated with CWE-770: Allocation of Resources Without Limits or Throttling.
An unauthenticated attacker with network access to the worker authentication listener can exploit this vulnerability remotely with low complexity and no user interaction required. By repeatedly opening connections and withholding the client certificate during the TLS handshake, the attacker can consume resources and block the worker from processing legitimate enrollments, leading to a denial-of-service condition that disrupts Boundary operations.
HashiCorp has addressed CVE-2026-7776 in Boundary releases 0.21.3, 0.20.3, and 0.19.5. Security practitioners should upgrade affected workers to one of these patched versions. Additional details are available in the HashiCorp security advisory at https://discuss.hashicorp.com/t/hcsec-2026-11-boundary-workers-vulnerable-to-denial-of-service-during-tls-handshake.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-27145
Vulnerability details
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…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes a remotely exploitable flaw in a network listener (worker authentication) that allows unauthenticated attackers to trigger resource exhaustion and block legitimate connections, directly enabling Exploit Public-Facing Application (T1190) to achieve Application or System Exploitation denial-of-service (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly protects against denial-of-service events like resource exhaustion from attackers delaying or withholding client certificates during TLS handshakes.
Ensures resource availability by implementing allocation controls and throttling to counter unthrottled connections causing worker blocking.
Mandates timely flaw remediation through patching, directly addressing and fixing the specific TLS handshake DoS vulnerability in Boundary workers.