#VU62883 Use-after-free in D-Bus - CVE-2020-35512

Vulnerability identifier: #VU62883

Vulnerability risk: Low

CVSSv4.0: 1.9 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-35512

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
D-Bus
Client/Desktop applications / Messaging software

Vendor: Freedesktop.org

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a use-after-free error if two usernames have the same numeric UID. When a set of policy rules references these usernames, D-Bus may free some memory in the heap, which is still used by data structures necessary for the other usernames sharing the UID, which can result in crash.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

D-Bus: 1.10.0 - 1.13.16

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External links
https://bugs.gentoo.org/755392
https://bugzilla.redhat.com/show_bug.cgi?id=1909101
https://gitlab.freedesktop.org/dbus/dbus/-/issues/305#note_829128
https://security-tracker.debian.org/tracker/CVE-2020-35512

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.