{"id":"GHSA-cqgj-h8vf-4w59","summary":"Acknowledgement extension out of memory","details":"### Impact\nBad 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.\n\nSuch bad clients would always send:\n\n```json\n{\n  \"channel\": \"/meta/connect\",\n  ...\n  \"ext\": { \"ack\": 1 }\n}\n```\n\nThe server would never clear the unacknowledged message queue, and one bad client can cause a server outage.\n\n### Patches\n5.0.x - https://github.com/cometd/cometd/pull/2168\n6.0.x - https://github.com/cometd/cometd/pull/2169\n8.0.x - https://github.com/cometd/cometd/pull/2118\n\n### Workarounds\nDisable the acknowledgement extension.\n\n### Resources\nhttps://github.com/cometd/cometd/discussions/2116\nhttps://github.com/cometd/cometd/issues/2117","aliases":["CVE-2025-53114"],"modified":"2026-06-10T17:11:27.329206Z","published":"2026-06-10T16:46:28Z","database_specific":{"cwe_ids":["CWE-400"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-06-10T16:46:28Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/cometd/cometd/security/advisories/GHSA-cqgj-h8vf-4w59"},{"type":"WEB","url":"https://github.com/cometd/cometd/issues/2117"},{"type":"WEB","url":"https://github.com/cometd/cometd/pull/2118"},{"type":"WEB","url":"https://github.com/cometd/cometd/pull/2168"},{"type":"WEB","url":"https://github.com/cometd/cometd/pull/2169"},{"type":"PACKAGE","url":"https://github.com/cometd/cometd"},{"type":"WEB","url":"https://github.com/cometd/cometd/discussions/2116"}],"affected":[{"package":{"name":"org.cometd.java:cometd-java-server-common","ecosystem":"Maven","purl":"pkg:maven/org.cometd.java/cometd-java-server-common"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.0.0"},{"fixed":"5.0.23"}]}],"versions":["5.0.0","5.0.1","5.0.10","5.0.11","5.0.12","5.0.13","5.0.14","5.0.15","5.0.16","5.0.17","5.0.18","5.0.19","5.0.2","5.0.20","5.0.21","5.0.22","5.0.3","5.0.4","5.0.5","5.0.6","5.0.7","5.0.8","5.0.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 5.0.22","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-cqgj-h8vf-4w59/GHSA-cqgj-h8vf-4w59.json"}},{"package":{"name":"org.cometd.java:cometd-java-server-common","ecosystem":"Maven","purl":"pkg:maven/org.cometd.java/cometd-java-server-common"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.0.19"}]}],"versions":["6.0.0","6.0.1","6.0.10","6.0.11","6.0.12","6.0.13","6.0.14","6.0.15","6.0.16","6.0.17","6.0.18","6.0.2","6.0.3","6.0.4","6.0.5","6.0.6","6.0.7","6.0.8","6.0.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 6.0.18","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-cqgj-h8vf-4w59/GHSA-cqgj-h8vf-4w59.json"}},{"package":{"name":"org.cometd.java:cometd-java-server-common","ecosystem":"Maven","purl":"pkg:maven/org.cometd.java/cometd-java-server-common"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.0.19"}]}],"versions":["7.0.0","7.0.1","7.0.10","7.0.11","7.0.12","7.0.13","7.0.14","7.0.15","7.0.16","7.0.17","7.0.18","7.0.2","7.0.3","7.0.4","7.0.5","7.0.6","7.0.7","7.0.8","7.0.9"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-cqgj-h8vf-4w59/GHSA-cqgj-h8vf-4w59.json","last_known_affected_version_range":"\u003c= 7.0.18"}},{"package":{"name":"org.cometd.java:cometd-java-server-common","ecosystem":"Maven","purl":"pkg:maven/org.cometd.java/cometd-java-server-common"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"8.0.0"},{"fixed":"8.0.9"}]}],"versions":["8.0.0","8.0.1","8.0.2","8.0.3","8.0.4","8.0.5","8.0.6","8.0.7","8.0.8"],"database_specific":{"last_known_affected_version_range":"\u003c= 8.0.8","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-cqgj-h8vf-4w59/GHSA-cqgj-h8vf-4w59.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}