CometD is a scalable comet implementation for web messaging. In versions 5.0.0 through 5.0.22, 6.0.0 through 6.0.18, 7.0.0 through 7.0.18, and 8.0.0 through 8.0.8, bad clients that always send a fixed batch value when the server is using the acknowledgement extension may cause the unacknowledged message queue to grow indefinitely, eventually causing an `OutOfMemoryError`. Versions 5.0.23, 6.0.19, 7.0.19, and 8.0.9 patch the issue. As a workaround, disable the acknowledgement extension.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable yes

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
cometd cometd affected
Version Status Constraints
>= 5.0.0, < 5.0.23 affected —
>= 6.0.0, < 6.0.19 affected —
>= 7.0.0, < 7.0.19 affected —
>= 8.0.0, < 8.0.9 affected —

No data.

No data.

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Vendors Products
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Project Subscriptions

Vendors Products
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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-cqgj-h8vf-4w59 Acknowledgement extension out of memory
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/cometd/cometd/discussions/2116 cve-icon
https://github.com/cometd/cometd/issues/2117 cve-icon
https://github.com/cometd/cometd/pull/2118 cve-icon
https://github.com/cometd/cometd/pull/2168 cve-icon
https://github.com/cometd/cometd/pull/2169 cve-icon
https://github.com/cometd/cometd/security/advisories/GHSA-cqgj-h8vf-4w59 cve-icon
History

Thu, 18 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Thu, 18 Jun 2026 18:15:00 +0000

Type Values Removed Values Added
First Time appeared Cometd
Cometd cometd
Vendors & Products Cometd
Cometd cometd

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description CometD is a scalable comet implementation for web messaging. In versions 5.0.0 through 5.0.22, 6.0.0 through 6.0.18, 7.0.0 through 7.0.18, and 8.0.0 through 8.0.8, bad clients that always send a fixed batch value when the server is using the acknowledgement extension may cause the unacknowledged message queue to grow indefinitely, eventually causing an `OutOfMemoryError`. Versions 5.0.23, 6.0.19, 7.0.19, and 8.0.9 patch the issue. As a workaround, disable the acknowledgement extension.
Title CometD has acknowledgement extension out of memory
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-18T17:33:39.552Z

Reserved: 2025-06-25T13:41:23.088Z

Link: CVE-2025-53114

cve-icon Vulnrichment

Updated: 2026-06-18T17:31:30.370Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-18T18:00:11Z

Weaknesses