corosync: A heap-based buffer overflow was found in Corosync's Totem Process Group (totempg) message reassembly
CVE-2026-81665 is fixed in 9 products on 1 platform, first by ALSA-2026:67872, released September 16, 2026. It is not reported as exploited. Patch Radar priority: High.
A heap-based buffer overflow was found in Corosync's Totem Process Group (totempg) message reassembly. When processing fragmented multicast messages, the buffer used to reassemble fragments lacks a runtime bounds check in release builds. A network-adjacent attacker able to send crafted multicast protocol messages to the cluster could cause a heap buffer overflow with attacker-controlled data. This can crash the Corosync daemon, causing a denial of service to the entire cluster, and may potentially allow further exploitation given sufficient heap-corruption control.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| corosync · RHEL 10 | 3.1.9-1.el10_0.3 | RHSA-2026:67881 | Sep 17, 2026 |
| corosync · RHEL 8 | 0:3.1.8-1.el8_10.2 | RHSA-2026:69277 | Sep 22, 2026 |
| corosync · RHEL 9 | 0:3.1.10-1.el9_8.2 | RHSA-2026:67873 | Sep 19, 2026 |
| corosync · almalinux 10 | 3.1.10-1.el10_2.2 | ALSA-2026:67872 | Sep 16, 2026 |
| corosync · almalinux 8 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 | Sep 21, 2026 |
| corosync · almalinux 9 | 3.1.10-1.el9_8.2 | ALSA-2026:67873 | Sep 16, 2026 |
| corosync · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosync · ol 10 | 0:3.1.10-1.el10_2.2 | ELSA-2026-67872 | Sep 29, 2026 |
| corosync · ol 8 | 0:3.1.8-1.el8_10.2 | ELSA-2026-69277 | Sep 23, 2026 |
| corosync · ol 9 | 0:3.1.10-1.el9_8.2 | ELSA-2026-67873 | Sep 22, 2026 |
| corosync · opensuse-leap 16.0 | 3.1.9-160000.4.1 | OPENSUSE-SU-2026:21887-1 | Sep 20, 2026 |
| corosync · rocky 10 | 0:3.1.10-1.el10_2.2 | RLSA-2026:67872 | Sep 17, 2026 |
| corosync · rocky 8 | 0:3.1.8-1.el8_10.2 | RLSA-2026:69277 | Sep 23, 2026 |
| corosync · rocky 9 | 0:3.1.10-1.el9_8.2 | RLSA-2026:67873 | Sep 17, 2026 |
| corosync · sles 15.6 | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 | Sep 16, 2026 |
| corosync · sles 15.7 | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 | Sep 16, 2026 |
| corosync · sles 16.0 | 3.1.9-160000.4.1 | SUSE-SU-2026:23850-1 | Sep 20, 2026 |
| corosync-debuginfo · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosync-debugsource · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosync-vqsim · RHEL 8 | 0:3.1.8-1.el8_10.2 | RHSA-2026:69277 | Sep 22, 2026 |
| corosync-vqsim · RHEL 9 | 0:3.1.10-1.el9_8.2 | RHSA-2026:67873 | Sep 19, 2026 |
| corosync-vqsim · almalinux 10 | 3.1.10-1.el10_2.2 | ALSA-2026:67872 | Sep 16, 2026 |
| corosync-vqsim · almalinux 8 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 | Sep 21, 2026 |
| corosync-vqsim · almalinux 9 | 3.1.10-1.el9_8.2 | ALSA-2026:67873 | Sep 16, 2026 |
| corosync-vqsim · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosync-vqsim · ol 10 | 0:3.1.10-1.el10_2.2 | ELSA-2026-67872 | Sep 29, 2026 |
| corosync-vqsim · ol 8 | 0:3.1.8-1.el8_10.2 | ELSA-2026-69277 | Sep 23, 2026 |
| corosync-vqsim · ol 9 | 0:3.1.10-1.el9_8.2 | ELSA-2026-67873 | Sep 22, 2026 |
| corosync-vqsim-debuginfo · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosynclib · RHEL 8 | 0:3.1.8-1.el8_10.2 | RHSA-2026:69277 | Sep 22, 2026 |
| corosynclib · RHEL 9 | 0:3.1.10-1.el9_8.2 | RHSA-2026:67873 | Sep 19, 2026 |
| corosynclib · almalinux 10 | 3.1.10-1.el10_2.2 | ALSA-2026:67872 | Sep 16, 2026 |
| corosynclib · almalinux 8 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 | Sep 21, 2026 |
| corosynclib · almalinux 9 | 3.1.10-1.el9_8.2 | ALSA-2026:67873 | Sep 16, 2026 |
| corosynclib · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosynclib · ol 10 | 0:3.1.10-1.el10_2.2 | ELSA-2026-67872 | Sep 29, 2026 |
| corosynclib · ol 8 | 0:3.1.8-1.el8_10.2 | ELSA-2026-69277 | Sep 23, 2026 |
| corosynclib · ol 9 | 0:3.1.10-1.el9_8.2 | ELSA-2026-67873 | Sep 22, 2026 |
| corosynclib-debuginfo · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| corosynclib-devel · RHEL 8 | 0:3.1.8-1.el8_10.2 | RHSA-2026:69277 | Sep 22, 2026 |
| corosynclib-devel · RHEL 9 | 0:3.1.10-1.el9_8.2 | RHSA-2026:67873 | Sep 19, 2026 |
| corosynclib-devel · almalinux 10 | 3.1.10-1.el10_2.2 | ALSA-2026:67872 | Sep 16, 2026 |
| corosynclib-devel · almalinux 8 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 | Sep 21, 2026 |
| corosynclib-devel · almalinux 9 | 3.1.10-1.el9_8.2 | ALSA-2026:67873 | Sep 16, 2026 |
| corosynclib-devel · amzn 2023 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 | Sep 28, 2026 |
| spausedd · RHEL 8 | 0:3.1.8-1.el8_10.2 | RHSA-2026:69277 | Sep 22, 2026 |
| spausedd · almalinux 8 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 | Sep 21, 2026 |
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