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Security Bulletin: Consul’s KV endpoint is vulnerable to denial of service

Security Bulletin


Summary

Consul and Consul Enterprise’s (“Consul”) key/value endpoint is vulnerable to denial of service (DoS) due to incorrect Content Length header validation. This vulnerability, CVE-2025-11374, is fixed in Consul Community Edition 1.22.0 and Consul Enterprise 1.22.0, 1.21.6, 1.20.8 and 1.18.12.

Vulnerability Details

CVEID: CVE-2025-11374

Description: Consul and Consul Enterprise’s (“Consul”) key/value endpoint is vulnerable to denial of service (DoS) due to incorrect Content Length header validation. This vulnerability, CVE-2025-11374, is fixed in Consul Community Edition 1.22.0 and Consul Enterprise 1.22.0, 1.21.6, 1.20.8 and 1.18.12.

CWE: CWE-770: Allocation of Resources Without Limits or Throttling

CVSS Source: HashiCorp Inc.

CVSS Base score: 6.5

CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

Affected Product(s)

Version(s)

Consul Community Edition

0.0.1 - 1.21.5

Consul Enterprise

1.21.0 - 1.21.5

1.20.0 - 1.20.7

1.19.0 - 1.19.9

1.18.0 - 1.18.11 

 

Note: Consul Enterprise 1.19 is no longer part of the Long-Term Support (LTS) versions therefore won’t get a fix for this finding. We strongly recommend customers upgrading to a newer version.

Remediation/Fixes

Customers using Consul’s should evaluate the risk associated with this issue and consider upgrading to Consul Community Edition 1.22.0 or Consul Enterprise 1.22.0, 1.21.6, 1.20.8 and 1.18.12.

See Consul’s Upgrading documentation for general guidance on this process.

Workarounds and Mitigations

None

Get Notified about Future Security Bulletins

References

Off

Link to HashiCorp bulletin

Consul’s KV endpoint allows customers to access Consul’s simple key/value store, useful for storing indexed objects, though its main uses are storing configuration parameters and metadata.

Excluding the Content-Length header in the Consul’s KV endpoint allowed an attacker to bypass the content length verification. This vulnerability allowed an attacker to send large payloads, which were copied into the buffer, potentially leading to a denial of service (DoS) or system instability due to memory exhaustion.

Acknowledgement

This issue was identified by Julien Ahrens from RCE Security (https://www.rcesecurity.com/).

Change History

07 Nov 2025: 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 November 2025

Initial Publish date:
07 November 2025

UID

ibm17250439