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Fencer Vulns
medium 5.5

CVE-2026-16730 json

Dbus-broker: dbus-broker: session bus denial of service via emfile during peer setup

published 2026-07-24 3 mo ago modified 2026-11-05 3 d ago also EUVD-2026-48559

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

A flaw was found in dbus-broker. When the process file-descriptor limit is reached, EMFILE/ENFILE errors during peer setup (notably SO_PEERPIDFD) are handled as fatal failures, causing the broker to exit. A local attacker who can open many connections to the user session bus can trigger this and deny service to the desktop session. Flatpak applications can reach the host session bus through the dbus proxy.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:36-5.el10_2
  • Red Hat Red Hat Enterprise Linux 9 0:28-9.el9_8
  • Red Hat Red Hat Update Infrastructure 5 1788765051, 1788880445, 1788880456, 1788880464, 1788880581
  • dbus-broker RHEL 9 28-9.el9_8
  • dbus-broker RHEL 10.2 36-5.el10_2

red hat advisories RHSA-2026:61355RHSA-2026:61340

  • dbus-broker AlmaLinux 10 36-5.el10_2
  • dbus-broker AlmaLinux 9 28-9.el9_8

almalinux advisories ALSA-2026:61340ALSA-2026:61355

  • dbus-broker Rocky Linux 10 36-5.el10_2
  • dbus-broker Rocky Linux 9 28-9.el9_8

rocky linux advisories RLSA-2026:61340RLSA-2026:61355

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-16730 updated cvss 5.5

dbus-broker: dbus-broker: session bus denial of service via EMFILE during peer setup

  • Red Hat Hardened Images dbus-broker 37-9.hum1
    affected: workaround, no fix available
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux BaseOS (v. 9) dbus-broker 28-9.el9_8
    fixed: vendor fix RHSA-2026:61355
  • Red Hat Enterprise Linux BaseOS (v. 10) dbus-broker 36-5.el10_2
    fixed: vendor fix RHSA-2026:61340
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1788880464, rhui5/rhua-rhel9 1788880581, rhui5/haproxy-rhel9 1788880456, rhui5/installer-rhel9 1788765051, rhui5/cds-kubernetes-rhel9 1788880445
    fixed: vendor fix RHSA-2026:66018

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Update Infrastructure 5
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.