CVE-2019-12749

dbus: DBusServer DBUS_COOKIE_SHA1 authentication bypass

Published Jun 11, 2019 CVSS 3.1 · 7.1 High EPSS < 1% KEV · Not listed
Description
dbus before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12, as used in DBusServer in Canonical Upstart in Ubuntu 14.04 (and in some, less common, uses of dbus-daemon), allows cookie spoofing because of symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. (This only affects the DBUS_COOKIE_SHA1 authentication mechanism.) A malicious client with write access to its own home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent client connection came from an attacker-chosen uid, allowing authentication bypass.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-1818-1 dbus security update
Debian DSA Debian DSA DSA-4462-1 dbus security update
EUVD EUVD EUVD-2019-4335 dbus before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12, as used in DBusServer in Canonical Upstart in Ubuntu 14.04 (and in some, less common, uses of dbus-daemon), allows cookie spoofing because of symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. (This only affects the DBUS_COOKIE_SHA1 authentication mechanism.) A malicious client with write access to its own home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent client connection came from an attacker-chosen uid, allowing authentication bypass.
Ubuntu USN Ubuntu USN USN-4015-1 DBus vulnerability
Ubuntu USN Ubuntu USN USN-4015-2 DBus vulnerability
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Feb 13, 2026, 7:57 PM
Reserved
Jun 6, 2019, 12:00 AM
Status
Modified
Published
Jun 11, 2019, 5:29 PM
Modified
Jun 17, 2026, 2:15 AM
Severity
Important
Public date
Jun 11, 2019, 12:00 AM