Security Bulletin
Summary
HashiCorp Consul and Consul Enterprise are vulnerable to a denial of service in the HTTP API that may allow an unauthenticated attacker to exhaust memory on a Consul agent. This vulnerability (CVE-2026-105626) is fixed in Consul Community Edition 2.1.0 and Consul Enterprise 2.1.0 and 1.21.19.
Vulnerability Details
CVEID: CVE-2026-105626
DESCRIPTION: Several Consul HTTP API endpoints read and decoded the entire request body into memory without a size limit before the caller's ACL permissions were evaluated. An attacker with network access to an agent's HTTP API could send very large request bodies, including to endpoints that do not require authentication, causing excessive memory consumption. Large or concurrent requests could degrade the agent or cause the operating system to terminate it, resulting in a denial of service. The issue requires network access to the HTTP API but does not require a valid ACL token.
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) |
| Consul Community Edition | affected from 0.6.0 up to 2.1.0 |
| Consul Enterprise | affected from 0.6.0 up to 2.1.0, unaffected from 1.21.19 |
Remediation/Fixes
Customers should evaluate the risk associated with this issue and consider upgrading to Consul Community Edition 2.1.0 or Consul Enterprise 2.1.0 or 1.21.19. After upgrading, most HTTP API write endpoints reject request bodies larger than 512 KiB, so operators who submit unusually large payloads, such as large configuration entries, should confirm their requests stay within this limit.
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References
Acknowledgement
This issue was reported to HashiCorp by Immad Sahin of ZeroTrail.
Change History
26 Oct 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
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Document Location
Worldwide
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Document Information
Modified date:
26 October 2026
Initial Publish date:
26 October 2026
UID
ibm17294120