# CVE-2026-10649: Pacemaker: pacemaker: denial of service via integer overflow in remote message decompression

Status: published. Published: 2026-06-16. Updated: 2026-11-04.

A flaw was found in Pacemaker. An unauthenticated remote attacker can exploit an integer overflow vulnerability in the remote message decompression process. By sending a specially crafted compressed remote message before authentication, an attacker can cause memory corruption, leading to a denial of service (DoS) in the CIB remote listener. This can result in the affected service crashing.

## Remediation

- workaround: Disable the Pacemaker CIB remote listener if it is not actively used. If the listener is required, restrict network access to trusted hosts by configuring firewall rules to limit inbound connections to the `remote-port` or `remote-tls-port`. These actions reduce the attack surface by limiting unauthenticated network exposure to the vulnerable component. A restart of the Pacemaker service may be necessary for these changes to be fully applied. (source: CNA: redhat)
- fix: RHSA-2026:43606: Red Hat Enterprise Linux Server HighAvailability (v. 7 ELS), Red Hat Enterprise Linux Server ResilientStorage (v. 7 ELS)

RHSA-2026:41041: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux High Availability EUS (v. 10.0)

RHSA-2026:40833: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux High Availability (v. 10)

RHSA-2026:39322: Red Hat Enterprise Linux AppStream (v. 8), Red Hat Enterprise Linux HighAvailability (v. 8), Red Hat Enterprise Linux ResilientStorage (v. 8)

RHSA-2026:42075: Red Hat Enterprise Linux AppStream AUS (v.8.4), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4), Red Hat Enterprise Linux High Availability AUS (v.8.4), Red Hat Enterprise Linux HighAvailability EUS EXTENSION (v.8.4)

RHSA-2026:42076: Red Hat Enterprise Linux AppStream AUS (v.8.6), Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6), Red Hat Enterprise Linux High Availability EUS EXTENSION (v.8.6)

RHSA-2026:42041: Red Hat Enterprise Linux AppStream E4S (v.8.8), Red Hat Enterprise Linux AppStream TUS (v.8.8), Red Hat Enterprise Linux High Availability E4S (v.8.8), Red Hat Enterprise Linux High Availability TUS (v.8.8)

RHSA-2026:41042: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux High Availability EUS (v.9.6), Red Hat Enterprise Linux Resilient Storage EUS (v.9.6)

RHSA-2026:39323: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux High Availability (v. 9), Red Hat Enterprise Linux Resilient Storage (v. 9)

RHSA-2026:41044: Red Hat Enterprise Linux High Availability E4S (v.9.2), Red Hat Enterprise Linux Resilient Storage E4S (v.9.2)

RHSA-2026:41043: Red Hat Enterprise Linux High Availability E4S (v.9.4), Red Hat Enterprise Linux Resilient Storage E4S (v.9.4) (source: ADP: redhat-SADP)
- workaround: Disable the Pacemaker CIB remote listener if it is not actively used. If the listener is required, restrict network access to trusted hosts by configuring firewall rules to limit inbound connections to the `remote-port` or `remote-tls-port`. These actions reduce the attack surface by limiting unauthenticated network exposure to the vulnerable component. A restart of the Pacemaker service may be necessary for these changes to be fully applied. (source: ADP: redhat-SADP)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (pacemaker): ≥ 0:3.0.1-5.el10_2.1; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (pacemaker): ≥ 0:3.0.0-5.3.el10_0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (pacemaker): ≥ 0:1.1.23-1.el7_9.2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (pacemaker): ≥ 0:2.1.7-5.6.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (pacemaker): ≥ 0:2.0.5-9.el8_4.12; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (pacemaker): ≥ 0:2.0.5-9.el8_4.12; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (pacemaker): ≥ 0:2.1.2-4.el8_6.11; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (pacemaker): ≥ 0:2.1.2-4.el8_6.11; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (pacemaker): ≥ 0:2.1.5-9.7.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.5-9.7.el8_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (pacemaker): ≥ 0:2.1.10-3.el9_8; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.5-9.el9_2.7; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.7-5.5.el9_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (pacemaker): ≥ 0:2.1.9-1.4.el9_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (pacemaker): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (pacemaker): ≥ 0:3.0.1-5.el10_2.1; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 10.0 Extended Update Support (pacemaker): ≥ 0:3.0.0-5.3.el10_0; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (pacemaker): ≥ 0:1.1.23-1.el7_9.2; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8 (pacemaker): ≥ 0:2.1.7-5.6.el8_10; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (pacemaker): ≥ 0:2.0.5-9.el8_4.12; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (pacemaker): ≥ 0:2.0.5-9.el8_4.12; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (pacemaker): ≥ 0:2.1.2-4.el8_6.11; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On (pacemaker): ≥ 0:2.1.2-4.el8_6.11; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (pacemaker): ≥ 0:2.1.5-9.7.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.5-9.7.el8_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9 (pacemaker): ≥ 0:2.1.10-3.el9_8; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.5-9.el9_2.7; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions (pacemaker): ≥ 0:2.1.7-5.5.el9_4; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 9.6 Extended Update Support (pacemaker): ≥ 0:2.1.9-1.4.el9_6; < * (unaffected, rpm). Source: ADP: redhat-SADP
- Red Hat / Red Hat Enterprise Linux 6 (pacemaker): Version range not reported. Source: ADP: redhat-SADP
- Red Hat / Red Hat OpenShift Container Platform 4 (rhcos): Version range not reported. Source: ADP: redhat-SADP

## Severity and prioritization

- CVSS 3.1: 8.6 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H; source: CNA: redhat

- CVSS 3.1: 8.6 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H; source: ADP: redhat-SADP

- CVSS 3.1: 8.6 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H; source: NVD: secalert@redhat.com

- CVSS 3.1: 8.6 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H; source: NVD: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

- CISA KEV: No listing in collected sources

- EPSS: 0.56% as of 2026-11-04; percentile 46.80%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-190

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:39322 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:39323 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:40833 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41041 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41042 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41043 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41044 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42041 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42075 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42076 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:43606 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-10649 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2462817 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://github.com/clusterLabs/pacemaker/pull/4128 (CNA: redhat)

- http://www.openwall.com/lists/oss-security/2026/06/16/6 (ADP: CVE)

- https://access.redhat.com/security/cve/CVE-2026-10649 (ADP: redhat-SADP; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2462817 (ADP: redhat-SADP; issue-tracking, x_refsource_REDHAT)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10649.json (ADP: redhat-SADP; x_sadp-csaf-vex)

- https://access.redhat.com/errata/RHSA-2026:43606 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41041 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:40833 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:39322 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42075 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42076 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:42041 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41042 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:39323 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41044 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:41043 (ADP: redhat-SADP; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:39322 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:39323 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:40833 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:41041 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:41042 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:41043 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:41044 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:42041 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:42075 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:42076 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2026:43606 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2026-10649 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2462817 (secalert@redhat.com)

- https://github.com/clusterLabs/pacemaker/pull/4128 (secalert@redhat.com)

- http://www.openwall.com/lists/oss-security/2026/06/16/6 (af854a3a-2127-422b-91ae-364da2661108)

- https://access.redhat.com/errata/RHSA-2026:39322 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:39323 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:40833 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:41041 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:41042 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:41043 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:41044 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:42041 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:42075 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:42076 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/errata/RHSA-2026:43606 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://access.redhat.com/security/cve/CVE-2026-10649 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://bugzilla.redhat.com/show_bug.cgi?id=2462817 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-10649.json (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-10649; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10649; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-10649; retrieved 2026-11-04; source updated Not reported

Revision: 941c697ddc760453eb222ab94eaad21272da0232cbb7320a73b85a657424d54a

Canonical: https://y2.dev/cve/CVE-2026-10649

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