# CVE-2026-120749: Dbus: dbus-daemon: dbus-daemon aborts (reply_serial != 0) when a broadcast from the driver cannot be delivered to a monitored bus

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

A flaw was found in D-Bus. With a privileged Monitoring client attached (for example dbus-monitor or busctl monitor), an unprivileged local user can cause dbus-daemon to abort if a driver-originated broadcast such as NameOwnerChanged or ActivatableServicesChanged cannot be delivered to a recipient (for example due to a deny rule or an exceeded outgoing message queue). Driver broadcasts still use serial 0; when delivery fails, composing the monitor error reply asserts reply_serial != 0 and aborts the daemon. This is an incomplete fix for CVE-2023-34969, which only assigned serials for driver messages sent to a single recipient. On the well-known system bus this is a denial of service.

## Remediation

- workaround: This can only be done if a monitoring process such as dbus-monitor or busctl monitor is active on the same dbus-daemon instance, which is a privileged operation that can only be done by root or the Unix uid of the message bus. If no monitoring process is active, then the vulnerable code is not reached. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (dbus): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (dbus): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (dbus): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (dbus): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (dbus): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Hardened Images (dbus): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.2 (medium); CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-617

## Exploit evidence

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

## References

- https://access.redhat.com/security/cve/CVE-2026-120749 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2567978 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://gitlab.freedesktop.org/dbus/dbus/-/merge_requests/565 (CNA: redhat)

- https://gitlab.freedesktop.org/dbus/dbus/-/merge_requests/592 (CNA: redhat)

- https://gitlab.freedesktop.org/dbus/dbus/-/work_items/576 (CNA: redhat)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-120749; retrieved 2026-11-06; source updated 2026-11-06

Revision: fee3e923f8953074ff7026d749b9b717e0741720d9f1328ffa719f92ecbd7fae

Canonical: https://y2.dev/cve/CVE-2026-120749

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