CVE-2026-81665

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.

High
CVSS
7.5
important
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0042
36th percentile

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

ProductFixed inFixReleased
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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