Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | — | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | — | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | — | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | corosync | No fix yet | — |
| Debian 13 | corosync | No fix yet | — |
| Debian 12 | corosync | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | corosync | No fix yet | — |
| Ubuntu 26.04 LTS | corosync | No fix yet | — |
| Ubuntu 24.04 LTS | corosync | No fix yet | — |
| Ubuntu 22.04 LTS | corosync | No fix yet | — |
| Ubuntu 20.04 LTS | corosync | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | corosync | No fix yet | — |
| Ubuntu 16.04 LTS | corosync | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | corosync +3 | 3.1.10-1.el10_2.2 | RHSA-2026:67872 |
| RHEL 9 | corosync +3 | 3.1.10-1.el9_8.2 | RHSA-2026:67873 |
| RHEL 8 | corosync +4 | 3.1.8-1.el8_10.2 | RHSA-2026:69277 |
| RHEL 7 | corosync +5 | 2.4.5-7.el7_9.4 | RHSA-2026:68574 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | corosync +3 | 3.1.9-1.el10_0.3 | RHSA-2026:67881 |
| RHEL 9.6 EUS | corosync +3 | 3.1.9-2.el9_6.2 | RHSA-2026:67879 |
| RHEL 9.4 E4S | corosync +2 | 3.1.8-1.el9_4.2 | RHSA-2026:67878 |
| RHEL 9.2 E4S | corosync +2 | 3.1.7-1.el9_2.2 | RHSA-2026:67880 |
| RHEL 8.8 TUS | corosync +3 | 3.1.7-1.el8_8.2 | RHSA-2026:69278 |
| RHEL 8.8 E4S | corosync +3 | 3.1.7-1.el8_8.2 | RHSA-2026:69278 |
| RHEL 8.6 EUS Long Life | corosync +3 | 3.1.5-2.el8_6.2 | RHSA-2026:69279 |
| RHEL 8.6 AUS | corosync +1 | 3.1.5-2.el8_6.2 | RHSA-2026:69279 |
| RHEL 8.4 EUS Long Life | corosync +3 | 3.1.0-3.el8_4.3 | RHSA-2026:69280 |
| RHEL 8.4 AUS | corosync +3 | 3.1.0-3.el8_4.3 | RHSA-2026:69280 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | corosync +3 | 3.1.10-1.el10_2.2 | ALSA-2026:67872 |
| AlmaLinux 9 | corosync +3 | 3.1.10-1.el9_8.2 | ALSA-2026:67873 |
| AlmaLinux 8 | corosync +4 | 3.1.8-1.el8_10.2 | ALSA-2026:69277 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | corosync | 3.1.10-1.el10_2.2 | RLSA-2026:67872 |
| Rocky Linux 9 | corosync | 3.1.10-1.el9_8.2 | RLSA-2026:67873 |
| Rocky Linux 8 | corosync | 3.1.8-1.el8_10.2 | RLSA-2026:69277 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP6 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP5 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP4 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 12 SP5 | corosync | 2.3.6-9.25.1 | SUSE-SU-2026:4387-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 16.0 | corosync | 3.1.9-160000.4.1 | SUSE-SU-2026:23850-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | corosync | 3.1.10-5.1 | openSUSE-SU-2026:11715-1 |
| openSUSE Leap 16.0 | corosync | 3.1.9-160000.4.1 | openSUSE-SU-2026:21887-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | corosync +3 | 3.1.9-3.amzn2023.0.3 | ALAS2023-2026-3138 |
| Amazon Linux 2 | corosync +5 | 2.4.3-6.amzn2.1.2 | ALAS2-2026-3955 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | corosync | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | corosync +2 | 3.1.10-1.el10_2.2 | ELSA-2026-67872 |
| Oracle Linux 9 | corosync +2 | 3.1.10-1.el9_8.2 | ELSA-2026-67873 |
| Oracle Linux 8 | corosync +2 | 3.1.8-1.el8_10.2 | ELSA-2026-69277 |
Advisories 28
- WID-SEC-2026-3419 Red Hat Enterprise Linux (corosync, libevent, libsoup): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALSA-2026:67873 Important: corosync security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:67872 Important: corosync security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:69277 Important: corosync security update AlmaLinux Security Advisories · Oct 29, 2026
- SUSE-SU-2026:4387-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 30, 2026
- RHSA-2026:69280 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:69279 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:69278 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:69277 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:68574 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67881 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67879 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67880 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67873 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67878 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- RHSA-2026:67872 Red Hat Security Advisory: corosync security update Red Hat Security Advisories (RHSA) · Sep 30, 2026
- ELSA-2026-67872 Important: corosync security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Sep 29, 2026
- ALAS2023-2026-3138 Important: corosync security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 28, 2026
- ALAS2-2026-3955 Important: corosync security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 28, 2026
- SUSE-SU-2026:23850-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 27, 2026
- openSUSE-SU-2026:21887-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 25, 2026
- RLSA-2026:69277 Important: corosync security update Rocky Linux Security Advisories · Sep 23, 2026
- ELSA-2026-69277 Important: corosync security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Sep 23, 2026
- ELSA-2026-67873 Important: corosync security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Sep 22, 2026
- RLSA-2026:67872 Important: corosync security update Rocky Linux Security Advisories · Sep 17, 2026
- RLSA-2026:67873 Important: corosync security update Rocky Linux Security Advisories · Sep 17, 2026
- SUSE-SU-2026:4202-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 16, 2026
- openSUSE-SU-2026:11715-1 corosync-3.1.10-5.1 on GA media SUSE / openSUSE Security Updates · Sep 9, 2026
References
- RHSA-2026:67872 vendor-advisory
- RHSA-2026:67873 vendor-advisory
- RHSA-2026:67878 vendor-advisory
- RHSA-2026:67879 vendor-advisory
- RHSA-2026:67880 vendor-advisory
- RHSA-2026:67881 vendor-advisory
- RHSA-2026:68574 vendor-advisory
- RHSA-2026:69277 vendor-advisory
- RHSA-2026:69278 vendor-advisory
- RHSA-2026:69279 vendor-advisory
- RHSA-2026:69280 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-81665 vdb-entry
- RHBZ#2524910 issue-tracking