#VU63053 Use-after-free in cron (Debian package) - CVE-2019-9706

Vulnerability identifier: #VU63053

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-9706

CWE-ID: CWE-416

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
cron (Debian package)
Operating systems & Components / Operating system package or component

Vendor: Debian

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 in force_rescan_user() function in Vixie Cron. A local user can write specially crafted data to the crontab file, trigger a use-after-free error and crash the daemon.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

cron (Debian package): 3.0pl1-100 - 3.0pl1-132

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External links
https://salsa.debian.org/debian/cron/commit/40791b93
https://packages.qa.debian.org/c/cron/news/20190311T170403Z.html
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=809167
https://lists.debian.org/debian-lts-announce/2019/03/msg00025.html
https://lists.debian.org/debian-lts-announce/2021/10/msg00029.html

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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.