#VU45886 NULL pointer dereference in Debian Linux - CVE-2020-16117

Vulnerability identifier: #VU45886

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-16117

CWE-ID: CWE-476

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Debian Linux
Operating systems & Components / Operating system

Vendor: Debian

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in GNOME evolution-data-server before 3.35.91, a malicious server can crash the mail client with a NULL pointer dereference by sending an invalid (e.g., minimal) CAPABILITY line on a connection attempt. This is related to imapx_free_capability and imapx_connect_to_server. A remote attacker can perform a denial of service (DoS) attack.

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Debian Linux: 9.0

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External links
https://gitlab.gnome.org/GNOME/evolution-data-server/-/commit/2cc39592b532cf0dc994fd3694b8e6bf924c9ab5
https://gitlab.gnome.org/GNOME/evolution-data-server/-/commit/627c3cdbfd077e59aa288c85ff8272950577f1d7
https://gitlab.gnome.org/GNOME/evolution-data-server/-/issues/189
https://lists.debian.org/debian-lts-announce/2020/08/msg00005.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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