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GHSA-cqgj-h8vf-4w59

Acknowledgement extension out of memory

Source: GitHub Advisory Database (reviewed) High CVE-2025-53114

Packages

EcosystemPackageAffectedFixed in
Maven org.cometd.java:cometd-java-server-common >= 5.0.0, < 5.0.23 5.0.23
Maven org.cometd.java:cometd-java-server-common >= 6.0.0, < 6.0.19 6.0.19
Maven org.cometd.java:cometd-java-server-common >= 7.0.0, < 7.0.19 7.0.19
Maven org.cometd.java:cometd-java-server-common >= 8.0.0, < 8.0.9 8.0.9

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact Bad clients that always send a fixed batch value while the server is using the acknowledgement extension can cause the unacknowledged message queue to grow indefinitely, eventually resulting in an OutOfMemoryError. Such bad clients would always send: ```json { "channel": "/meta/connect", ... "ext": { "ack": 1 } } ``` The server would never clear the unacknowledged message queue, and one bad client can cause a server outage. ### Patches 5.0.x - https://github.com/cometd/cometd/pull/2168 6.0.x - https://github.com/cometd/cometd/pull/2169 8.0.x - https://github.com/cometd/cometd/pull/2118 ### Workarounds Disable the acknowledgement extension. ### Resources https://github.com/cometd/cometd/discussions/2116 https://github.com/cometd/cometd/issues/2117

References

External links from the advisory. They lead to third-party sites.