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
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.
Fixes and workarounds
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: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 10 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 6 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Hardened Images Red Hat dbus
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 6.2 medium |
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-120749CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2567978CNA: redhat · issue-tracking, x_refsource_REDHAT
- https://gitlab.freedesktop.org/dbus/dbus/-/merge_requests/565CNA: redhat
- https://gitlab.freedesktop.org/dbus/dbus/-/merge_requests/592CNA: redhat
- https://gitlab.freedesktop.org/dbus/dbus/-/work_items/576CNA: redhat
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