CVE-2018-6557: Insecure temporary file use in base-files

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-08-21 · updated 2026-06-17
Weakness: CWE-59

Description

The MOTD update script in the base-files package in Ubuntu 18.04 LTS before 10.1ubuntu2.2, and Ubuntu 18.10 before 10.1ubuntu6 incorrectly handled temporary files. A local attacker could use this issue to cause a denial of service, or possibly escalate privileges if kernel symlink restrictions were disabled.

Affected products

Base-Files Project Base-Files: 10.1ubuntu2.2
Canonical Ubuntu Linux: 18.04, 18.10

References

http://www.securityfocus.com/bid/105148
http://www.securitytracker.com/id/1041530
https://usn.ubuntu.com/3748-1/
http://www.securityfocus.com/bid/105148
http://www.securitytracker.com/id/1041530
https://usn.ubuntu.com/3748-1/

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