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Security Bulletin: Authorization bypass for session deletion in the transaction API

Security Bulletin


Summary

Consul Community Edition and Consul Enterprise 1.19.1 through 2.0.2 did not enforce the session:write ACL permission for session deletion operations submitted through the transaction API. An authenticated caller with network access to the Consul server RPC port could delete arbitrary sessions without holding the required permission. This vulnerability, CVE-2026-19016, is fixed in Consul 2.0.3 and Consul Enterprise 1.21.17, 1.22.11, and 2.0.3.

Vulnerability Details

CVEID: CVE-2026-19016
DESCRIPTION: The transaction handler enforced ACL checks for several operation types but did not include a corresponding check for session deletion operations. The dedicated session API correctly requires session:write permission before permitting a session to be modified or deleted. Because this check was absent from the transaction path, a caller could perform session deletion operations without holding the required permission. Exploitation requires network access to the Consul server RPC port and knowledge of the randomly-generated session ID. Enabling mutual TLS on the RPC port limits unauthenticated exploitation by requiring callers to hold a valid client certificate, but does not fully mitigate the issue for authenticated callers that lack session:write permission. Successful exploitation could disrupt distributed locks, leader election workflows, and service health coordination that rely on sessions.
CWE: CWE-22: Improper Limitation of a Pathname to a Restricted Directory (Path Traversal)
CVSS Source: HashiCorp Inc.
CVSS Base score: 4.2
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L)

Affected Products and Versions

Affected Product(s)Version(s)
Consul Community Editionaffected from 1.19.1 up to 2.0.3
Consul Enterpriseaffected from 1.19.1 up to 2.0.3, unaffected from 1.21.17, 1.22.11

Remediation/Fixes

Customers should evaluate the risk associated with this issue and consider upgrading to Consul 2.0.3 or Consul Enterprise 1.21.17, 1.22.11, or 2.0.3.

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References

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Acknowledgement

This issue was reported by Andres Cruciani.

Change History

07 Aug 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:
07 August 2026

Initial Publish date:
07 August 2026

UID

ibm17282996