{"id":"CVE-2026-42209","summary":"FlashMQ: Division by zero crash when using non-default deferred retained message setting","details":"FlashMQ is a MQTT broker/server, designed for multi-CPU environments. Prior to version 1.26.1, a remote client with retained publish permission can crash the FlashMQ broker when both set_retained_message_defer_timeout and set_retained_message_defer_timeout_spread are configured to non-default values, resulting in denial of service. If anonymous retained publishing is allowed, no authentication is required; otherwise, the attacker needs the corresponding publish permission. This issue has been patched in version 1.26.1.","aliases":["GHSA-2789-vfcg-5922"],"modified":"2026-07-15T01:49:12.167168458Z","published":"2026-05-08T21:40:43.284Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-369"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42209.json"},"references":[{"type":"WEB","url":"https://github.com/halfgaar/FlashMQ/releases/tag/v1.26.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42209.json"},{"type":"ADVISORY","url":"https://github.com/halfgaar/FlashMQ/security/advisories/GHSA-2789-vfcg-5922"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42209"},{"type":"REPORT","url":"https://github.com/halfgaar/FlashMQ/issues/167"},{"type":"FIX","url":"https://github.com/halfgaar/FlashMQ/commit/193b6e7767889511cfa8e933908ea5e6a1077a1f"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/halfgaar/flashmq","events":[{"introduced":"0"},{"fixed":"193b6e7767889511cfa8e933908ea5e6a1077a1f"},{"fixed":"a326649e16eee1fa6ff74c87b103eb8eb601b5cf"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"1.26.1"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["v1.26.0","v1.25.0","v1.24.0","v1.23.0","v1.22.0","v1.21.1","v1.21.0","v1.20.0","v1.19.0","v1.18.2","v1.18.1","v1.18.0","v1.17.2","v1.17.1","v1.17.0","v1.16.0","v1.15.4","v1.15.3","v1.15.2","v1.15.1","v1.15.0","v1.14.0","v1.13.1","v1.13.0","v1.12.1","v1.12.0","v1.11.0","v1.10.0","v1.9.1","v1.9.0","v1.8.4","v1.8.3","v1.8.2","v1.8.1","v1.8.0","v1.7.11","v1.7.10","v1.7.9","v1.7.8","v1.7.7","v1.7.6","v1.7.5","v1.7.4","v1.7.3","v1.7.2","v1.7.1","v1.7.0","v1.6.9","v1.6.8","v1.6.7","v1.6.6","v1.6.5","v1.6.4","v1.6.3","v1.6.2","v1.6.1","v1.6.0","v1.5.0","v1.4.5","v1.4.4","v1.4.3","v1.4.2","v1.4.1","v1.4.0","v1.3.1","v1.3.0","v1.2.1","v1.2.0","v1.1.0","v1.0.2","v1.0.1","v1.0.0","v0.13.1","v0.13.0","v0.12.1","v0.12.0","v0.11.9","v0.11.8","v0.11.7","v0.11.6","v0.11.5","v0.11.4","v0.11.3","v0.11.2","v0.11.1","v0.11.0","v0.10.1","v0.10.0","v0.9.9","v0.9.8","v0.9.7","v0.9.6","v0.9.5","v0.9.4","v0.9.3","v0.9.2","v0.9.1","v0.9.0","v0.8.1","v0.8.0","v0.7.1","v0.7.0","v0.6.3","v0.6.1","v0.6.0","v0.5.2","v0.5.1","v0.5.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42209.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}