CVE-2018-20836 Use after free in n/a

What is CVE-2018-20836?

CVE-2018-20836 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 7 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An issue was discovered in the Linux kernel before 4.20. There is a race condition in smp_task_timedout() and smp_task_done() in drivers/scsi/libsas/sas_expander.c, leading to a use-after-free.

Weakness: CWE-416, CWE-362

Which versions are affected by CVE-2018-20836?

It affects 13 products.

Products include Canonical Ubuntu Linux, Debian Debian Linux, F5 Traffix Signaling Delivery Controller, Linux kernel, Netapp Active Iq Unified Manager, Netapp Hci Compute Node and 7 more.

How do I fix CVE-2018-20836?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2018-20836 being exploited?

There is no known exploitation of CVE-2018-20836 in the wild and no public exploit code.

Other vulnerabilities in Canonical Ubuntu Linux

• CVE-2020-11651 SaltStack Salt Authentication Bypass Exploited Critical 9.8
• CVE-2020-7247 OpenSMTPD Remote Code Execution Exploited Critical 9.8
• CVE-2019-16928 Exim Out-of-bounds Write Exploited Critical 9.8
• CVE-2018-6789 Exim Buffer Overflow Exploited Critical 9.8
• CVE-2015-2590 Oracle Java SE and Java SE Embedded Remote Code Execution Exploited Critical 9.8

All Canonical Ubuntu Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2018-20836, GHSA-hjqh-c7g9-6w2x, UBUNTU-CVE-2018-20836.